Update bower.json to depend on jquery not jQuery

**See #ichord/At.js#157** (just merged)

It appears Bower will happily resolve *both* jQuery and jquery:
in projects that specify both Caret.js and other dependencies relying
on jQuery, Bower will attempt to install jQuery twice, possibly with
differing versions.

In the case of a case insensitive filesystem (Windows and Mac, by
default), the jQuery components directory will be overwritten/merged.
See: bower/bower#1150

https://www.openproject.org/work_packages/7310