REDESIGNED: `LoadDirectoryFiles()`
ADDED: `LoadDirectoryFilesEx()`
REDESIGNED: `LoadDroppedFiles()`
ADDED: `IsPathFile()`

This BIG BREAKING change simplifies the functions and gives more control to the user:
 - A new `struct FilePathList` has been added to avoid exposing complex pointers.
 - User is responsible of memory loading/unloading
 - Filepaths loading support recursive directories and file extension filters

RENAMED: `ClearDroppedFiles()` to `UnloadDroppedFiles()`

RENAMED: GetCodepoints() -> LoadCodepoints(), now codepoint array data is loaded dynamically instead of reusing a limited static buffer.
ADDED: UnloadCodepoints() to safely free loaded codepoints
RENAMED: GetNextCodepoint() -> GetCodepoint()

* Added support for additional mouse buttons

* Renamed mouse button enum

Co-authored-by: Lambert Wang <lambert.ww@gmail.com>