Add support for remapping class name prefixes

Adds support for interpreting "CL: xxx/* yyy/*" in .srg for remapping
all class names beginning with xxx/ to yyy/. Previously this functionality
was only programmatically accessible when SpecialSource was used as a
library, but now you can use it from .srg mappings as well.

May be replaced with "PK: xxx yyy" support in .srg files later,
but needs to be first thoroughly tested for full compatibility,
to ensure identical semantics as in MCP (e.g. remapping ".").

Adding CL: /* class name prefix remapping for now, separate from PK:,
which simply remaps class names matching the given prefix substring.