Basic MIPS support
Merge pull request #56 from KarlVogel/mips-support

Mips support
Bump minimal Python 2.x version to 2.7

This lets me banish a local version of OrderedDict, which has issues submitted
against it (e.g. pull request #53).

Python 2.7 has been out for a while now, it's time to move on. I haven't been
testing pyelftools on 2.6 for some time anyway.
Remove outdated TODO instruction
Changes for release 0.23