Let Travis run gae test

I add to add a test runner since 
`nosetests --with-gae` cannot be run with
python 2.6. So the test runner check the python 
version before loading GAE.

(the runner doesn't use nose.core.main
since I fail to make it load the gae plugin)
fix test after change of API.get return value
AppEngineAPI.send_request return non-200 results
Renamed NOGAE to NO_GAE
rename travis test runner
Explicitly target python 2.7 and fix a comment

Those test will be skipped in python 3 too
(in case evelink starts to support it).
Add a script to download the last GAE SDK

For travis.
Add documentation and arg parser to Travis script

Also, if the the GAE install fail and the test
runner cannot load GAE, it won't exit. It will 
instead run test and skip the gae related ones.
upgrade distribute
Remove feedparser dependency

Using sudo may be changing which python is used
for the pre-script script
install GAE in evelink directory...

... and not in /usr/local/bin so that the 
before-script doesn't need to be run with sudo.
Merge pull request #146 from martinehrenthal/gae-travis

Enable the Travis-CI build to include AppEngine tests.