Revert "Use jquery-rails from github (fix Gem::Version error)"

This reverts commit 6f3f0f86332004fcee5c2f05d52bbff08c22f980.
Revert "Use jquery-rails from github"

This reverts commit 7a9a7007637b8279501770be03bd84ce83d61ab8.

Conflicts:
	railties/lib/rails/generators/app_base.rb