Add Get{Min,Max,Range}() to numeric validator classes

Just provide accessors matching the existing setters.

Closes https://github.com/wxWidgets/wxWidgets/pull/1287,
https://github.com/wxWidgets/wxWidgets/pull/1288

include/wx/valnum.h

@@ -157,17 +157,33 @@ public:
         this->DoSetMin(min);
     }
 
+    ValueType GetMin() const
+    {
+        return static_cast<ValueType>(this->DoGetMin());
+    }
+
     void SetMax(ValueType max)
     {
         this->DoSetMax(max);
     }
 
+    ValueType GetMax() const
+    {
+        return static_cast<ValueType>(this->DoGetMax());
+    }
+
     void SetRange(ValueType min, ValueType max)
     {
         SetMin(min);
         SetMax(max);
     }
 
+    void GetRange(ValueType& min, ValueType& max) const
+    {
+        min = GetMin();
+        max = GetMax();
+    }
+
     virtual bool TransferToWindow()  wxOVERRIDE
     {
         if ( m_value )
@@ -288,7 +304,9 @@ protected:
     static bool FromString(const wxString& s, LongestValueType *value);
 
     void DoSetMin(LongestValueType min) { m_min = min; }
+    LongestValueType DoGetMin() const { return m_min; }
     void DoSetMax(LongestValueType max) { m_max = max; }
+    LongestValueType DoGetMax() const { return m_max; }
 
     bool IsInRange(LongestValueType value) const
     {
@@ -390,7 +408,9 @@ protected:
     bool FromString(const wxString& s, LongestValueType *value) const;
 
     void DoSetMin(LongestValueType min) { m_min = min; }
+    LongestValueType DoGetMin() const { return m_min; }
     void DoSetMax(LongestValueType max) { m_max = max; }
+    LongestValueType DoGetMax() const { return m_max; }
 
     bool IsInRange(LongestValueType value) const
     {

interface/wx/valnum.h

@@ -89,6 +89,13 @@ public:
      */
     void SetMin(ValueType min);
 
+    /**
+        Gets the minimal value accepted by the validator.
+
+        @since 3.1.3
+     */
+    ValueType GetMin() const;
+
     /**
         Sets the maximal value accepted by the validator.
 
@@ -96,6 +103,13 @@ public:
      */
     void SetMax(ValueType max);
 
+    /**
+        Gets the maximum value accepted by the validator.
+
+        @since 3.1.3
+     */
+    ValueType GetMax() const;
+
     /**
         Sets both minimal and maximal values accepted by the validator.
 
@@ -103,6 +117,12 @@ public:
      */
     void SetRange(ValueType min, ValueType max);
 
+    /**
+        Gets both minimal and maximal values accepted by the validator.
+
+        @since 3.1.3
+     */
+    void GetRange(ValueType& min, ValueType& max) const;
 
     /**
         Change the validator style.