Unbreak Nexuiz weapon animation.

Unbreak Nexuiz weapon animation.

Nexuiz uses h_*.dpm models that are mostly vertex-less (there are 6 dummy ones)
and merely move bones in order to move around the first-person weapon.

This means that these models (or rather, their surface meshes) will be
considered "non-animated" by the rendering code, given their dummy vertices are
never moved by animations.

However, a function to build animation subframes lists from animation group
numbers - which is called by gettaginfo and similar functions that locate
attachment points - falsely looked at the isanimated flag of the surface mesh
to decide whether to really build the list of subframes or not - and this was
wrong, given that statically displayed models that do move tags/bones do exist!

This commit removes this use of the isanimated flag and treats models with
animated and non-animated surface mesh the same for purposes of animation frame
evaluation.

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12241 d7cf8633-e32d-0410-b094-e92efae38249