Core (LV::Palette): Add methods for iteration.

Author: kaixiong

libvisual/libvisual/lv_palette.h

@@ -45,6 +45,9 @@ namespace LV {
   //!
   struct LV_API Palette
   {
+      using const_iterator = std::vector<Color>::const_iterator;
+      using iterator = std::vector<Color>::iterator;
+
       std::vector<Color> colors;
 
       /**
@@ -80,6 +83,36 @@ namespace LV {
           return !(lhs == rhs);
       }
 
+      constexpr const_iterator cbegin () const noexcept
+      {
+          return colors.cbegin ();
+      }
+
+      constexpr const_iterator cend () const noexcept
+      {
+          return colors.cend ();
+      }
+
+      constexpr const_iterator begin () const noexcept
+      {
+          return colors.begin ();
+      }
+
+      constexpr const_iterator end () const noexcept
+      {
+          return colors.end ();
+      }
+
+      constexpr iterator begin () noexcept
+      {
+          return colors.begin ();
+      }
+
+      constexpr iterator end () noexcept
+      {
+          return colors.end ();
+      }
+
       bool empty () const
       {
           return colors.empty ();