message: Allow user to override ImTextureId.
diff: @@ -74,11 +74,14 @@ struct ImGuiListClipper; // Helper to manually clip large list of ite
  struct ImGuiPayload; // User data payload for drag and drop operations
  struct ImGuiContext; // ImGui context (opaque)
  +#ifndef ImTextureID
  +typedef void* ImTextureID; // user data to identify a texture (this is whatever to you want it to be! read the FAQ about ImTextureID in imgui.cpp)
  +#endif
  +
  // Typedefs and Enumerations (declared as int for compatibility and to not pollute the top of this file)
  typedef unsigned int ImU32; // 32-bit unsigned integer (typically used to store packed colors)
  typedef unsigned int ImGuiID; // unique ID used by widgets (typically hashed from a stack of string)
  typedef unsigned short ImWchar; // character for keyboard input/display
  -typedef void* ImTextureID; // user data to identify a texture (this is whatever to you want it to be! read the FAQ about ImTextureID in imgui.cpp)
  typedef int ImGuiCol; // enum: a color identifier for styling // enum ImGuiCol_
  typedef int ImGuiCond; // enum: a condition for Set*() // enum ImGuiCond_
  typedef int ImGuiKey; // enum: a key identifier (ImGui-side enum) // enum ImGuiKey_
  