This series of commits forms part 1 of my GSoC project, wherein I finish implementing and cleaning up the binary buffer functions.

Done:

• Fix variant's bitwise operators
• Switch BinaryBuffer to use std::byte and std::size_t
• Add serialization and deserialization (big-endian) for the various types supported
• Fix almost all the functions to be as conformant to GMS's behaviour as possible
• Give enums names (buffer_seek_t, buffer_type_t, buffer_data_t) to enforce strict typing
• Tests for most functions
• Documentation for all except game_save_buffer and game_load_buffer

Only 9 functions are remaining now, I've gone over 32 of them. I'm not really sure how to implement the async functions, and I have no real idea how buffer_set_used_size is supposed to work.

Checklist of the various functions:

• buffer_exists
• buffer_create
• buffer_create_from_vertex_buffer
• buffer_create_from_vertex_buffer_ext
• buffer_delete
• buffer_read
• buffer_write
• buffer_fill
• buffer_seek
• buffer_tell
• buffer_peek
• buffer_poke
• buffer_save
• buffer_save_ext
• buffer_save_async
• buffer_load
• buffer_load_ext
• buffer_load_async
• buffer_load_partial
• buffer_compress
• buffer_decompress
• buffer_async_group_begin
• buffer_async_group_option
• buffer_async_group_end
• buffer_copy
• buffer_copy_from_vertex_buffer
• buffer_get_type
• buffer_get_alignment
• buffer_get_address
• buffer_get_size
• buffer_get_surface
• buffer_set_surface
• buffer_resize
• buffer_sizeof
• buffer_md5
• buffer_sha1
• buffer_crc32
• buffer_base64_encode
• buffer_base64_decode
• buffer_base64_decode_ext
• buffer_set_used_size