update flask dependecy

[ael-code]

some minor changes to support the new flask version 0.11.1

importing stuff from flask.ext was deprecated and we were using it
only for babel

fixes #297

[boyska]

Is this new "style" also ok with old flask? I'd like to keep everything in debian stable supported (so maybe I should add an explicit test case in .travis.yml, right)

[ael-code]

Is this new "style" also ok with old flask? I'd like to keep everything in debian stable supported (so maybe I should add an explicit test case in .travis.yml, right)

I've tested also with old Flask version. In any case it's better if we make travis run tests also with Flask 0.10.

[boyska]

ael:

Is this new "style" also ok with old flask? I'd like to keep everything in debian stable supported (so maybe I should add an explicit test case in .travis.yml, right)

I've tested also with old Flask version. In any case it's better if we make travis run tests also with Flask 0.10.

I am working on it; if I manage to do it soon, then merge that before
merging this. Otherwise, just merge this and I trust you to behave.

[boyska]

#300 should do it. I also rebased this PR over #299 in a branch of mine to check if everything was ok, and it is. So you are free to rebase&merge, but please have a look at #300, too