Fix py2

[manodeep]

Fixing #214

[manodeep]

Explanation from @1313e as to why installing in editable mode is necessary on TRAVIS:

The reason for it is that on Travis CI (specifically on Linux), the working directory is set to the root of the package. If you install it the normal way and then try to import it, the local package takes priority over the installed package (see my notes on how Python imports work from last year). As you haven't built that, it cannot find any files and crashes.

For further reference on how imports work in python, see here

[lgarrison]

Only real question is the extra CHANGES.rst entry