added flash notice for cart update
installed spinjs-rails
set up spinner to show cart update in progress
cleaned up JS and added CSS for spinner location
added spinner toggle for update of reserver
added spinner toggle and flash for add / remove item actions
removed margin from spinner
[BROKEN] consolidated pause and resume cart functionality, trying to disable cart
fixed issues with session when disabling cart
merge development into 528_short_term_cart_fix
updated CHANGELOG for #528
removed commented-out CSS code
updated CSS comment
updating gemfile.lock
Merge branch '528_short_term_cart_fix' of github.com:YaleSTC/reservations into 528_short_term_cart_fix
Merge pull request #528 from YaleSTC/528_short_term_cart_fix

Short-term cart fix being merged in!
#447 copied announcement views and controller from branch announcements_ui
#477 changed date fields to use jquery datepicker
#447 form update.
#447 #421 to do: restrict announcement end date