* WindowBase: Added on_drop_begin, on_droptext and on_drop_end events.
* WindowBase: Renamed on_dropfile event/method to on_drop_file.
* WindowSDL: Dispatching mouse pos with dropbegin event.
* WindowBase: Updated docs for on_drop_xxx events.
* WindowBase: Removed code from on_drop_file method.
* WindowBase: Updated docs for on_drop_begin and on_drop_end events.
* WindowSDL: Updated _mouse_(x|y) attributes on dropbegin event.
* SDL2: Change return type from Uint8 to Uint32 for mouse state functions to match their signature from SDL_mouse.h.
* WindowSDL: Update mouse_pos value and dispatch of on_cursor_enter event.
* WindowBase: Use same type for mouse_pos (tuple) and _density (float) properties.
* WindowBase: Passing window relative mouse pos in on_drop_begin event and skip mousewheel if the cursor pos is not within the window size.
* added SDL_SetWindowHitTest function definitions, and data types
* Added custom_titlebar, custom_titlebar_handler_callback to handle titlebar and resize logic
* added custom_titlebar function
* removed SDL_WINDOWEVENT_HIT_TEST from WindowEventID
* made SDL_HITTEST_DRAGGABLE conditional
* added custom_titlebar in graphics section
* added custom_titlebar as WindowBase propetry
* added custom_titlebar in setup_window
* added custom_titlebar to setup_screen and post init set_border_state
* changed default_language_version to python3
* Implemented Window specific API to Support Aero Snapping
* when custom_title, set borderless state according to platform
* Added conditionl calling of in_drag_function; check for propretry draggable
* Set borderless state depending on platform
* add condition to compile windows specific code on windows only
* group windows code together
* fix resize issue after first drag of window (on windows platform)
* Made use of class _WindowsSysDPIWatch to set WM_NCCALCSIZE
* added variable WM_NCCALCSIZE
* moved the winproc hook code to window_sdl.py
* added handling when custom_titlebar is false on windows
* set_custom_titlebar returns True on 0
* added example for set_custom_titlebar
* changed checking conditions in set_custom_titlebar
* added custom_titlebar_border; bump up config version
* fixed Win32 patform test
* check for resizeable when using custom_titlebar
closes#5279
Mak Sim