VBA rerecording V21 changelog

Summary

Previous version resolution:

• V21 fixes the emulation bug that v20 did (Echo RAM bug fix). However, it does so without breaking compatibility with 19.x movies!
• V20 bugs/regressions are not present in v21 (basically v21 takes 19.3 and re-fixed it in a much better way).

New Features:

• Lua scripting implemented! For a listing of lua functions, see EmulatorResources/VBA/LuaScriptingFunctions.
• Lag counter implemented.

Bug Fixes:

• Fixed 'xn' window size would not reset when clicking on the option that is already checked.
• Fix for not recording the lag Reduction flag in GBA movies caused by using Ctrl-key-combos right before opening the recording.
• Fix crash caused by trying to open a file that doesn't exist and ends with .gba
• Fix crash caused by the sequence "Load movie, use cheat search, close movie, open new movie, open cheat search".
• Fixed a fatal bug that VBA doesn't clear out SRAM before movie playback.
• Fixed RTC snapshot length problem.

Feature enhancements:

• Drag and drop for movie files.
• Merged the movie play and movie record menu items.