Upgrade both site and docs to Bootstrap 3 (flatly)

Critical dependency on this site merge and the ngdocs merge being done at the same time.
Create translation entries for pt_BR
Fix #1643 (expandable): missing plus sign
fix(uiGridCell): Use promises for tmpl processing

Issue #1712 demonstrates a race condition where a column's
compiledElementFn is attempted to be called before the cellTemplate is
present, e.g. in the case of a template fetched over the network. This
causes the function to not be present and an exception to be thrown.

This changes fixes this by added a getCompiledElementFn() method to
GridColumn, which returns a promise that is created in the
defaultColumnBuilder(). It gets resolved in
Grid.preCompileCellTemplates(). uiGridCell now uses this promise if the
function is not present at pre-link time.

Added tests for getCompiledElementFn() and getCellTemplate()

Fixes #1712
Merge pull request #1749 from raulcesar/translation_pt_BR

Create and correct translation entries for pt_BR
Merge pull request #1732 from KiwiNiksta/flatly-only-bs3

Upgrade both site and docs to Bootstrap 3 (flatly)
Merge pull request #1752 from angular-ui/fix-http-templates

Fix url-based templates by using promises to retrieve the compiled function
Update to new grunt-ngdocs for bootstrap update
chore(Site): Add ngAnimate to index for menu animations
Fix #1753 (colMenu): size correctly with animations, hide on scroll or drag
Merge pull request #1755 from PaulL1/1753_column_width_animations

Fix #1753 (colMenu): size correctly with animations, hide on scroll or d...
fix(uiGridUtil): getBorderSize() missing "width"

The correct property name to use is "borderWidth", not just "border".
"border" works in Chrome but was breaking in Firefox.

Also had to change .ui-grid-header's box-sizing to content-box so IE11
would include the border in height calcs. AND finally IE11 was returning
fractional heights so Grid parseInt()s the returned values.
Fix: upgraded customizer to bootstrap flatly 3

Fix customizer page with bootstrap 3 upgrade, because it was missed when site and ngdocs were upgraded.

fix button label
Merge pull request #1764 from KiwiNiksta/customizer-bs3

Fix: upgraded customizer to bootstrap flatly 3
fix(Customizer): Update column menu style
fix(Selection): Remove IE11 ellipsis in header

For some reason IE11 turns the &nbsp; in the selection row header's header
cell into an ellipsis. Adding text-overflow: clip to .ui-grid-contents
fixes this but as a custom headerCellTemplate has to be defined, the
easier thing is just to remove all the unneeded stuff from the header cell
completely.

This change will probably be overwritten if and when we use the header
cell to actually do something.
Remove unused class

[skip ci]
fix(Site): Fix version select box height

The version select box was too short, caused by an explicit "height: 30px"
in docs.css. This update references a new version that removes that style.
fix(Travis): Make travis run saucelabs tests

After 2bdd734b5e28 it looks like the serialsauce task isn't getting run on
travis, so we haven't been doing any cross-browser testing for a month...

Hopefully this change will do the right if-checks in bash and let the
trask run.
fix(Grid): Fix a few mobile-browser issues

1. Allow 0-sized scrollbars, which pertains to Android and iOS in my
testing. The scrollbar simply doesn't get displayed. This prevents their
weird horizontal offset issue. The downside is that there's no scrollbar
but so far I can't find a way around it.

2. Fix header cell touch events. Sorting by touch should work, as well as
showing the menu by long-clicking on the header cell.

What still remains is all the other touch events (row selection, header
cell menu button, etc).