Fix long-hidden inconsistency in internal interface: 'find_modules()' now represents packages as strings, not tuples.  This allowed a simplification in 'get_package_dir()', too -- can now assume that 'package' is a string.
Fix long-hidden inconsistency in internal interface: 'find_modules()' now
represents packages as strings, not tuples.  This allowed a simplification
in 'get_package_dir()', too -- can now assume that 'package' is a string.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator