ENH: Add export-ignore to compiled python files

Since Python uses just-in-time compilation, the compiled binaries
(.pyc and .pyo files) are not something you would want to include
in an archive of a python code base.

Hence we add an export-ignore attribute to these file extensions.

Python.gitattributes

@@ -16,9 +16,9 @@
 *.p      binary
 *.pkl    binary
 *.pickle binary
-*.pyc    binary
+*.pyc    binary export-ignore
+*.pyo    binary export-ignore
 *.pyd    binary
-*.pyo    binary
 
 # Jupyter notebook
 *.ipynb  text