Conflictresolution within the same component

[ohumbel]

In case of a conflict, it makes sense to only propose change sets from the same component.
This pull request implements this.
Fixes #52

[WtfJoke]

From #52

But the usage of enum is only supported from python 3.4 on (see https://docs.python.org/3/library/enum.html). Therefore the python 3.3 build fails. I did not know that, and enum came in handy.

There are 2 ways to fix that:

disable the 3.3 build
do not use enum

@WtfJoke Manuel what do you propose?

IMHO it is acceptable to require a quite recent version of python.

Lets break the compatibility with 3.3 and disable the build of it. Couple of months ago I wrote in the readme that python 3.4 is required. So I think it shouldnt be a big deal.