gruntfile - no need to be specific about which image types
update jquery to 1.11.0

update jquery to 1.11.0, so there is no `event.returnValue is deprecated. Please use the standard event.preventDefault() instead.` warning by default.
Merge pull request #272 from zhuangya/patch-1

update jquery to 1.11.0
Fix-273 Exceptions on execution beginning and never finished.

Change grunt-contrib-imagemin version to the latest
Merge pull request #274 from oaleynik/master

Fix-273 Exceptions on execution beginning and never finished.
upgrade bower-install to 1.0
Merge pull request #276 from stephenplusplus/master

upgrade bower-install to 1.0
install bower_components in root directory

/app should only have user created/editable files. Bower should install
its files alongside npm's.

Fixes #171