Merge branch 'terencehill/menu_remove_tab_title' into 'master'

Menu: Remove tab title attribute

* Don't set the title for tabs since it's the tab button that holds and displays the tab title
* Don't spawn dialog borders (including title) for each tab contained in a dialog

I started this branch when I noticed that a few tab titles didn't match the corresponding tab button text, thus adding unused strings for translation (e.g. "Join" vs "Servers", "Demo" vs "Demos", etc...)

See merge request !126

diff --cc qcsrc/menu/xonotic/dialog_settings_game_crosshair.qc
Simple merge