add watch section for less files

* bumped version to 1.2.0
* fixed typo in js/docs/view.js
* added missed Changelog for 1.1.0 and 1.1.1
* add watcher for less files
* karma/lib/config.js now also found when using nix
* run multiple travis jobs for 2 browsers at the time
Merge pull request #11 from plone/garbas-watch-less

add watch section for less files