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.

Exec Summary: 
- Upgraded both the ui-grid site and the ngdocs for API and Tutorial. Now both on Bootstrap-flatly 3.2.  Both merges need to go together.

- Docs (API and Tutorial pages) are responsive - to a point.  Only responsive to 767px - great on the iPad, tiny on the iPhone, user can stretch and scroll :-).

- Cleaned out all excess bootstrap files, just have the bootstrap-flatly.min.css now.

- All testing complete. Good on tablet (except the known issue that iPads etc don't respond to click events on the grid).

I have listed out the changes in more detail below, but I am confident that this is good to go. Please let me know if you want any more info.

Best
Nic


Detailed list of changes:   There were 3 types of changes for this upgrade as follows: 

1. Responsive Tutorial and API pages: 
The API & Tutorial docs is responsive.  It can shrink to a minimum size of 767px wide.  Smaller is too hard to read - responsive down to tablet-size.  Tested each page on MacBook and on iPad mini

2. Cleaned out excess bootstrap.css files 
I cleaned out all Bootstrap files other than the bootstrap-flatly.min.css.  The dom was cluttered and my ability to unpick the requisite changes was challenged with so many overrides, so I cleaned them out.  
This required a minor change to the gruntfile.js.


3. Bootstrap-flatly upgrade to 3.2.0 - multiple changes
Site index & css: 
- Improved centering for the jumbotron (easier in bootstrap 3)
- Updated the body to use the bootstrap 3 grid, so that it behaves differently from smallest, to medium, to full width devices, and is nicely centred in all 3 sizes.
- Upgraded the navbar for bootstrap 3 (still uses bootstrap jquery :-()

For the ngdocs - most changes done in the ui-grid project, but also had to change the ngdocs index and docs.css. 
- Main body is responsive (container-fluid) but minimum size set to 767px. Smaller viewports need to scroll.
But the navbar is not fluid because the collapse button would disappear out to the right for smaller devices and the navbar doesn’t scroll. 
- Navbar - upgraded index and css. Can have a collapsed mode using angular (yay - no query!), but only kicks in for views smaller than the minimum that I’ve set.  
- Breadcrumbs upgraded - bootstrap has ::before to provide the “/“ between crumbs.
- Sidebar navigation - bootstrap 3 doesn’t have the “nav-list” styles (deprecated and not exactly replaced).  Therefore, coped them from the bootstrap-flatly version 2 into our doc.css - easier to keep than try and rebuild! 
- Upgraded the nav.html template - used for ngdocs.
- Modal css changes required a fix to tutorial 110.
- Minor color and spacing changes to use flatly but keep a consistent look-and-feel between version 2 and 3. 
- Also made a couple of fixes to api docs .js files for a couple of the directive tests that I noticed in manual testing.

Upgrade Bugs still open:
The only remaining issues are iPad touch not triggered for click events, existing issue.