Extending selection to full lines and removing browser added formatting

This pull request is related to [this issue](https://github.com/daviferreira/medium-editor/issues/172) where Google Chrome (v33 at the time of writing) browser automatically inserts inline styles when doing (un)orderedlist insertions.

Pull request adds two changes:

1. it executes `removeFormat` command on lists and default commands (*append-*, *anchor* and *image* commands are excluded)
2. it extends selection to full line when executing list commands - this is necessary because list commands convert whole lines and not just selected text; so when one doesn't select the whole line and executes list command, the whole line would get formatted but only selected text would have removed formatting (previously mentioned inline styles); that's why selection is being extended to full line, so no inline styles are being added to markup.