Give the users customizable axis label limits (Fixes ChartsOrg#2085) (ChartsOrg#2894)

* Give the users customizable axis label limits (Fixes ChartsOrg#2085)

This change adds the ability to users to override the imposed limitation of at least 2 labels per axis and at most 25 labels per axis at their own risk. By default these customizable limits are hardcoded to the previous limits, at least 2 labels, at most 25.

* Type inference was enough to declare 'axisMinLabels' and 'axisMaxLabels' properties

Author: igzrobertoestrada

Source/Charts/Components/AxisBase.swift

@@ -213,6 +213,16 @@ open class AxisBase: ComponentBase
     /// the total range of values this axis covers
     @objc open var axisRange = Double(0)
 
+    /// The minumum number of labels on the axis
+    @objc open var axisMinLabels = Int(2) {
+        didSet { axisMinLabels = axisMinLabels > 0 ? axisMinLabels : oldValue }
+    }
+    
+    /// The maximum number of labels on the axis
+    @objc open var axisMaxLabels = Int(25) {
+        didSet { axisMinLabels = axisMaxLabels > 0 ? axisMaxLabels : oldValue }
+    }
+    
     /// the number of label entries the axis should have
     /// max = 25,
     /// min = 2,
@@ -228,13 +238,13 @@ open class AxisBase: ComponentBase
         {
             _labelCount = newValue
 
-            if _labelCount > 25
+            if _labelCount > axisMaxLabels
             {
-                _labelCount = 25
+                _labelCount = axisMaxLabels
             }
-            if _labelCount < 2
+            if _labelCount < axisMinLabels
             {
-                _labelCount = 2
+                _labelCount = axisMinLabels
             }
 
             forceLabelsEnabled = false