Refactor uiGridController to move refresh and other methods to grid

All unit tests pass.  Need to modify buildStyles to not take $scope,
I couldn't find any styleComputations that actually used it, and it
appeared that all had access to uiGridCtrl, which is the same thing
that the scope would have provided.  Some risk there.

I was unable to register the public api, I suspect that is because
the api doesn't exist without a callback, so I needed to write it
as a onRegisterApi, but that's not imperative to this current
refactor.

I've written no new unit tests as yet, although clearly they're
possible with a lot of functions moved to Grid.js.  I don't know
what most of them do to unit test them well.
Merge pull request #1516 from PaulL1/refactor_gridctrl

Refactor uiGridController to move refresh and other methods to grid
bugfix(travis): Hopefully let PRs run tests

Travis doesn't give PRs access to secure variables (for good reason),
which means they can't connect to SauceLabs. These changes should prevent
the build process from trying to run CI tests on PRs and instead just run
local tests.

Also coverage and release tasks should only run on master branch commits

[skip ci]
bugfix(Scrolling): denormalize scroll wrong for FF

denormalizeScrollLeft() was returning scrollLeft * -1 for all scroll
events in FF when it should only have been when the grid was in RTL mode.
merging
Merge branch '3.0-subgrid' of github.com:yayasoft/ng-grid into 3.0-subgrid