Added GM:OnPauseMenuShow
This is meant to replace other methods of hiding the mainmenu (which will be disabled at some point). Return false to prevent main menu from showing for that key press.
The user can hold SHIFT to bypass this hook at any time, in case the server/addon has malicious intent of not allowing the player access the main menu.
Panel:GetFont works for RichText
Hammer builds on newer C++ Windows toolset
Limit GM:OnPauseMenuShow to ESC key