Ignore development files

[joscha]

This removes some files of the bower component, e.g.:

    CHANGELOG.md
    Gruntfile.js
    karma.conf.js
    package.json
    src/flow.js

[AidasK]

Should we remove src/flow.js? I think it is too late to remove src/flow.js, because it might be used be others.

[joscha]

it's in dist already. I think releasing it with a minor version bump should be okay, as the fix is quite easy and the error simple to detect.