* Balance the UI tests job, second half currently 8 min longer

* Upgrade mocha to 3.1.0

* rebalance

* Remove old mocha

Fixes #8041, fixing UI test issues (some at least) on travis by upgrading to mocha-2.2.5. Appears to fix random seg fault recently experienced.

(cherry picked from commit e7f236e)

move UI config to test folder and allow optionally to define a local config that will not be commited