message: Removed unnecessary extension files from MANIFEST.in
diff: # Include the license file
  include LICENSE
  -
  -# Include the ACSF header file
  -include dscribe/libacsf/acsf.h
  -include dscribe/libacsf/acsf.cpp
  -
  -# Include the MBTR source files
  -include dscribe/libmbtr/mbtr.h
  -include dscribe/libmbtr/mbtr.cpp
  