import-checker: accept .pyc and .pyo files (issue4812)
Python 2.6.1 (r261:67515, Jun 24 2010, 21:47:49)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
$ ls '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6'/BaseHTTPServer.py*
/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/BaseHTTPServer.pyc
/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/BaseHTTPServer.pyo