Use package ignored by codec generator

[willkamp]

Within com/codec_generator.py at line 38 the "if '.' in used_package:" check looks like it should have an else clause.
It appears that line 41,42,43 are indented once too often.

[LarsAsplund]

@willkamp Yes, this is a bug and you've found the root cause. I will commit a fix and some test cases. Thanks for reporting.