[#952] Update Jquery to latest version (1.9.0) in skeletons

Currently, jQuery 1.7.1 is embedded in new projects. It's an outdated version (Nov 2011), and this dependency is not necessary anymore.

As discussed on the [ML](https://groups.google.com/forum/?fromgroups=#!topic/play-framework-dev/zBfJp5eNSvE), this library should be upgraded to latest version for 2.1 Milestone, and then (maybe) totally removed.

I haven't updated the samples, I don't think it's necessary. If I'm wrong, tell me I'll do it.