Aint much, but its honest work

• Two new messageEntities, strikethrough and underline
• nested messageEntities, we have a PR for that somewhere
• New parsemode, MardownV2
• New file_unique_id for Animation, Audio, Document, PassportFile, PhotoSize, Sticker, Video, VideoNote, Voice, File
• small_file_unique_id and big_file_unique_id to the object ChatPhoto.
• custom_title for ChatMember
• new method setChatAdministratorCustomTitle
• new slow_mode_delay for Chat object