relocated the CL_SendMove call to put it at the end of network parsing (and only...

relocated the CL_SendMove call to put it at the end of network parsing (and only called if there was an svc_time message in this packet), this should greatly improve consistency of ping times and input sending (which was sometimes falling way behind with lag), no longer uses sys_ticrate to control input frequency
changed CL_TraceLine to CL_TraceBox and made it return a trace_t
worked on CL_ClientMovement function for clientside movement simulation (not working yet), this has many cl_movement* cvars associated with it which will be updated by the server at some point in the future
added (currently unused and not updated) cl_gravity and cl_slowmo cvars, which the server will be setting at some point in the future

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@5211 d7cf8633-e32d-0410-b094-e92efae38249