[Core] Settings improvements: Grouping w/labels, support for doubles (#137)

* [Core] Settings improvements: Grouping w/labels, support for doubles

Layout improvements:
* Plugins can set `[SettingSuggestedColumnWidth(123)]` on a settings class to adjust the settings view column width to make it wider or narrower to fit things nicely.
* Plugins can set `[SettingNewGroup("label")]` on any setting property to force a "new paragraph", or group, of settings. If "label" is also provided, a grouping header with that text will also be created.
* A double precision up/down numeric control has been added. In support of this, there is now a precision value on the existing `[SettingNumericBounds]` attribute to specify the number of digits of precision the control displays/allows.

Plugins:
* The above have been applied/demonstrated on the Botanist and Explorer plugin settings.

ObservatoryFramework/Attributes.cs

@@ -6,6 +6,32 @@ using System.Threading.Tasks;
 
 namespace Observatory.Framework
 {
+
+    #region Settings class attributes
+    /// <summary>
+    /// Specifies the width of a settings column in the settings view. There are two columns.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]
+    public class SettingSuggestedColumnWidth : Attribute
+    {
+        /// <summary>
+        /// Specifies the width of a settings column in the settings view. There are two columns.
+        /// </summary>
+        /// <param name="width">Provides a hint of the width of a settings column.</param>
+        public SettingSuggestedColumnWidth(int width)
+        {
+            Width = width;
+        }
+
+        /// <summary>
+        /// Provides a hint of the width of a settings column.
+        /// </summary>
+        public int Width { get; }
+    }
+    #endregion
+
+    #region Setting property attributes
+
     /// <summary>
     /// Specifies text to display as the name of the setting in the UI instead of the property name.
     /// </summary>
@@ -34,17 +60,24 @@ namespace Observatory.Framework
     }
 
     /// <summary>
-    /// Suggests default column width when building basic UI
+    /// Starts a new visual group of settings beginning with the current setting with an optional label.
     /// </summary>
     [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field)]
-    public class ColumnSuggestedWidth : Attribute
-    { 
-        public ColumnSuggestedWidth(int width)
+    public class SettingNewGroup : Attribute
+    {
+        /// <summary>
+        /// Starts a new visual group of settings beginning with the current setting with an optional label.
+        /// </summary>
+        /// <param name="label">An optional label describing the group.</param>
+        public SettingNewGroup(string label = "")
         {
-            Width = width;
+            Label = label;
         }
 
-        public int Width { get; } 
+        /// <summary>
+        /// An optional label describing the group.
+        /// </summary>
+        public string Label { get; }
     }
 
     /// <summary>
@@ -97,6 +130,7 @@ namespace Observatory.Framework
         private double minimum;
         private double maximum;
         private double increment;
+        private int precision;
 
         /// <summary>
         /// Specify bounds for numeric inputs.
@@ -104,11 +138,13 @@ namespace Observatory.Framework
         /// <param name="minimum">Minimum allowed value.</param>
         /// <param name="maximum">Maximum allowed value.</param>
         /// <param name="increment">Increment between allowed values in slider/roller inputs.</param>
-        public SettingNumericBounds(double minimum, double maximum, double increment = 1.0)
+        /// <param name="precision">The number of digits to display for non integer values.</param>
+        public SettingNumericBounds(double minimum, double maximum, double increment = 1.0, int precision = 1)
         {
             this.minimum = minimum;
             this.maximum = maximum;
             this.increment = increment;
+            this.precision = precision;
         }
 
         /// <summary>
@@ -121,7 +157,7 @@ namespace Observatory.Framework
         }
 
         /// <summary>
-        /// Maxunyn allowed value.
+        /// Maximum allowed value.
         /// </summary>
         public double Maximum
         {
@@ -137,5 +173,38 @@ namespace Observatory.Framework
             get => increment;
             set => increment = value;
         }
+
+        /// <summary>
+        /// The number of digits to display for non integer values.
+        /// </summary>
+        public int Precision
+        {
+            get => precision;
+            set => precision = value;
+        }
     }
+    #endregion
+
+    #region BasicUI attributes
+    /// <summary>
+    /// Suggests default column width when building basic plugin grid UI.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field)]
+    public class ColumnSuggestedWidth : Attribute
+    {
+        /// <summary>
+        /// Suggests default column width when building basic plugin grid UI.
+        /// </summary>
+        /// <param name="width">The suggested width of the annotated column.</param>
+        public ColumnSuggestedWidth(int width)
+        {
+            Width = width;
+        }
+
+        /// <summary>
+        /// The suggested width of the annotated column.
+        /// </summary>
+        public int Width { get; }
+    }
+    #endregion
 }