rewrote timing code, now a much better and very different sleeping method, no longer...

rewrote timing code, now a much better and very different sleeping method, no longer wastes any cpu time
changed timing code to have independent sleeping for client and server frames in a listen server
changed console execution to occur in sync with server frames if a server is running, this fixes frikbot loading of .way files
eliminated several host_* variables, replaced host_realframetime with cl.realframetime (which is how long since the last client frame)
removed the clamping of sys_ticrate to >= 0.1, so now sys_ticrate 0 is allowed (run as fast as possible), as well as silly values like 0.001
removed serverprofile cvar as it was not easy to preserve it in the rewritten timing
merged Host_FilterTime, Host_ServerFrame, Host_Frame, _Host_Frame into Host_Main (which also calls Host_Init), this eliminates some duplicate code in all the sys_ modules

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@6300 d7cf8633-e32d-0410-b094-e92efae38249