added explict checks for source tv and replay
even where IsFakeClient() is called and may catch replay i have added checks
this will allow us to determine if replay being added is a case of insufficient checks
also fixed a case whereby, when pyros are allowed, a client would be switched to solly
changed build listener to switch to primary
this may or may not work as a fix, we need to test it in game
however i'm hopeful
http://docs.sourcemod.net/api/index.php?fastload=show&id=243&
add cvar tf2_hidden_allowengineer
Re-factor CanPlay function