OBJ_LOADER_DEMO: Fix typo in normal map paths
OBJ_HMF_CONVERTER: Don't store duplicate strings in the string table
OBJ_LOADER_DEMO: Update sponza hmf with optimized string table data
COMMON: Remove redundant variable assignment
OBJ_LOADER_DEMO: Fix ModelSubset assignment

TODO: Use an actual constructor instead of implicit construction by values