Move GritResourceMap arrays (~12,500 bytes) to read-only data segment
Due to a quirk in VC++ it is easy to accidentally prevent a const global
array from being placed in the read-only data segment. This change
removes a should-be-harmless 'const' keyword to work around this quirk
and move ~12,500 bytes to the .rdata (read-only) data segment in
VC++ bug is filed here:
Other instances of this quirk have also been worked around.