Slightly mapped out the CMDLCache class, to the point the pointers to its members are no longer needed. Also fixed a bug were the studiodata pointer was dereferenced before checking if its not null, this check did exist, but was performed too late. Fully implemented the CUtlDict class for m_MDLDict. Slightly optimized the initialization of the error model handles.
This fixes the exceptions that were caused by loading ported bsps with replaced models
CStaticProp::Init was using static prop lump data to request non-existent skins due to the replaced models, causing invalid material pointers to be fetched.
When encountered, these skins will be forced to 0 and an error will be printed.
Ideally these issues are fixed from within the bsp file before they are shipped.
