Merge branch 'terencehill/quickmenu' into 'master'

Quick menu

A quick menu that can be activated in game (default key b) with a default set of commands / settings.

Entry's names can be translated as well as messages in say / say_team commands but I made it optional (default hud_panel_quickmenu_translatecommands 0) so that a player can send default messages in English clicking on the relative entry's name in their language.

Commands that toggle a cvar shows a checkbox with the current state.

Commands like "tell" ("Send private message to" entry) show a list of players from which you can pick one, so the command is directed to the selected player.

It can optionally load custom quickmenus from files by setting hud_panel_quickmenu_file to <file_name>.

See merge request !207