Removed unused vertex/triangle optimization code

When enabled, the renderer won't compile.
When this is fixed, map load times are increased dramatically without any improvement to runtime performance and very little difference to vertex/index counts.
Remove unused shader "models/buildables/drill/energy".
Add back a commented version of "models/buildables/drill/energy" since it's used by the low poly drill model.
Cleanup a cast inside generic_vp.glsl.
Error out if an extra pak can not be found
Make modelist print to regular log not developer. Remove extra newlines
Remove unused variable
When the areaportalMask changes invalidate all cached clusters.

Invalidating only the current view cluster is not enough, because the
player can walk back into an already cached cluster which then would
be drawn based on the old areamask setting.
Slightly improve IQM culling. This doesn't fix all the problems though
Relax path validation to only disallow consecutive / or .
Remove --console-log-level=warn from download-pk3-torrent.sh since debian's current aria2 version doesn't support it.
Only continue flushing stdin if data has actually been read.

Code as was would repeatedly call read() until it returned -1. However,
read() returns 0 at EOF (and I've seen this function spin because of this),
and I've read that ‘some other implementations’ may return -2.
Fix smooth alpha blending.
Fix cvar parsing in commands executed via modcase.
Explicitly set aria2's download target in download-pk3-torrent.sh so it won't get overwritten by user configuration.
Kill off the alien upgrade icon in favour of the upgraded class icons.
Add back the /dir cmd
Allow use of wildcards in listCvars
Fix FS_GetFileList not looking in fs_homepath/game/, also fix layout completion in /map and /devmap
Merge branch 'master' into coverity_scan