added GL_DepthRange function and MATERIALFLAG_SHORTDEPTHRANGE (now used by viewmodels...

added GL_DepthRange function and MATERIALFLAG_SHORTDEPTHRANGE (now used by viewmodels), this prevents viewmodels from poking into walls
changed EF_NODEPTHTEST code to set MATERIALFLAG_SHORTDEPTHRANGE instead of MATERIALFLAG_NODEPTHTEST, this causes proper rendering of opaque models (such as the held item in prydon gate)
this also reenabled stencil shadows on view models but they render as if they are very very small (due to MATERIALFLAG_SHORTDEPTHRANGE)
changed default value of cl_viewmodel_scale from 0.3 to 1, this makes stereo rendering look better (small gun model looks silly when you can actually see that it is small) and makes rtlight cubemaps affect the gun more realistically

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@7068 d7cf8633-e32d-0410-b094-e92efae38249