Fix TableTools paths with asset_path() and image-url()

By renaming TableTools.js to TableTools.js.erb, we can use a dynamic
asset path for the default path to the clipboard SWFs. This allows
TableTools to be used without overriding `sSwfPath` on each
initialization.

The image paths in TableTools.css and TableTools_JUI.css were using
paths rooted at '/assets'. When mounting an application outside of the
host root, this causes them to fail. By renaming the files to .scss
we can use the Sass image-url() function rather than just url().
Upgrade TableTools (2.1.5) and Bootstrap integration

 * Pull in changes to TableTools for 2.1.5
 * Add defaults for TableTools to Bootstrap integration

Note: the min.js is as in the distributed packaged, the same as before.
Fix up ColVis CSS and support jQuery 1.9

 * Add ColVis CSS files under SCSS extension for image-url use
 * Add button.png, which is used by ColVisAlt.css
 * Include safety valve for jQuery 1.9 / MSIE 6 detection from 1.1-dev