Final cleanup to tracemalloc library. The source is now completely encapsulated using preprocessors. The header now only includes the functions calls and stddef.h.
Removed tracemalloc's <string.h> from header which was causing a dependency in bitmap.c and added to the file as it should be.
If we ever decide to fully remove the tracemalloc library in the future, it is now for the most part completely decoupled from the engine.
