Update korlib for texture caching

Previously, the C korlib used a custom buffer class to avoid a memcpy
operation. However, pyMipmap expects binary string (PyBytes) objects, so
this changes the code to use them. Future work would be to continue
using PyBytes and removing the copy. For now, there are bigger fish to
fry...

korlib/CMakeLists.txt

@@ -18,7 +18,6 @@ endif()
 
 # Da files
 set(korlib_HEADERS
-    buffer.h
     bumpmap.h
     korlib.h
     sound.h
@@ -26,7 +25,6 @@ set(korlib_HEADERS
 )
 
 set(korlib_SOURCES
-    buffer.cpp
     bumpmap.cpp
     module.cpp
     sound.cpp