Update GDash UI with Bootstrap 2.x + responsive designed thumbnails

In this branch, I've updated GDash to use the latest version of bootstrap and jquery (with server-side compiled less).

I also replaced the table-based HTML markup with the bootstrap thumbnail gallery, and included the bootstrap responsive design component with the default bootstrap breakpoints.

In removing the tables, I also changed the code to use the .graph filename in the graph permalink, rather than the array index.