Fix CONTENT_TYPE and CONTENT_LENGTH handling

[fbbdev]

Fix #15

[coveralls]

Coverage increased (+0.2%) to 65.974% when pulling 71be407 on content-length-type into b4612a5 on master.

[coveralls]

Coverage increased (+0.2%) to 65.974% when pulling 71be407 on content-length-type into b4612a5 on master.

[coveralls]

Coverage increased (+0.2%) to 65.974% when pulling 71be407 on content-length-type into b4612a5 on master.

[robertgroh]

@fbbdev:
Thank you very much for your work.
This fixed bug (#15) could be a explanation for some strange behaivor, which I always suspected to be the result our buggy code at work.

It is nice to see, that you document such bugs as own issues and add a test for the fix.
I hope more developers would also do the same.

Your work is very appreciated.

[fbbdev]

@robertgroh:
Now this made me blush 😊. I have to thank you in turn, because with your pull request you taught me to write tests and how to write them, and this is being beneficial to other projects I'm working on. It also enhanced my development workflow in many ways and made it much more comfortable.

Please report an issue if you see that buggy behavior again, I'd be happy to investigate. #15 was introduced in the 1.1.0 rewrite. Previous versions should not be affected.