Updated count_function_calls doctests.
Fixed several migration-related FIXME items in experimental.

Only five migration-related FIXME items remain in experimental:

    musicexpressiontools/test/test_IterablePayloadExpression__callbacks.py
    189:    py.test.skip('FIXME: Broke after TypedList stopped inheriting from
    list.')

    scoremanagertools/managers/FileManager/test/test_FileManager_interactively_remove.py
    28:@py.test.skip('FIXME: Broken by git migration')

    scoremanagertools/managers/FileManager/test/test_FileManager_public_attributes.py
    22:@py.test.skip('FIXME: Broken by git migration.')

    scoremanagertools/managers/FileManager/test/test_FileManager_remove.py
    28:@py.test.skip('FIXME: Broken by git migration.')

    scoremanagertools/managers/FileManager/test/test_FileManager_rename.py
    7:@py.test.skip('FIXME: Broken by class package flattening.')

These five remaining items will be fixed in coming commits.