Refactor: Reimplemented MaterialAnim as a C++ class
Refactor: Allocate storage for MaterialAnims from the real heap

Allocating these from the Zone is of no benefit and only serves to
add another block which the rovers must skip over (the only times
at which these are (de)allocated is during an engine reset or when
a new add-on is loaded from the console).
Relocated MaterialAnim to material.cpp/h
Refactor|MaterialBind: Minor MaterialBind cleanup refactorings
Refactor|Materials: Continued cleanup refactorings
Fix typos
Refactor|Materials: Revised material system animation group interface
Cleanup