use proper print() and except syntax to support python 3

[MorrisJobke]

This allows the usage in Python 3. I didn't tested everything, but this solved a lot of problems. It only contains two types of changes:

• print "value" to print("value") which is available since 2.6: https://docs.python.org/2.7/library/functions.html#print
• except Exception, e: to except Exception as e: which also is available since 2.6: http://stackoverflow.com/a/2535770 https://docs.python.org/2/reference/compound_stmts.html#the-try-statement

[MorrisJobke]

cc @svanoort

[MorrisJobke]

The tests run fine on python2.7: CodeforChemnitz/SensorAPI#1

I currently debug why they fail on python3.4+

[svanoort]

Thank you for taking the time to offer this!
It would be helpful (especially since python3 support is a necessary and helpful feature) and useful.
However, I do see it has merge conflicts at this time. Would it be possible to fix those, for the moment in order to allow a clean integration of changes?

Thanks,
Sam

[svanoort]

@MorrisJobke Note that there was a small bug with HTTP headers not being handled in a case-insensitive fashion before this, which I have fixed. Also I have resolved the merge conflict.

I'm holding off advertising full Python3 compatibility until I have automated test coverage included (it's on my to-do list with Jenkins testing of pyresttest). However this will be going out along with my next release!