pr2_msgs catkinized

[130s]

Not tested, built fine on local machine. Not sure if catkinizing a pkg without the stack that containing it is catkinized works.

[130s]

@ahendrix What's wrong with my pull req?

[ahendrix]

Mostly, it's against the old groovy-devel branch, when it should be targeted into hydro.

A few other things:

• Partial catkinization doesn't help much; the whole stack should be catkinized
• You've marked it at "not tested" which doesn't inspire confidence
• You added the messages to the build, but missed the services
• You neglected to do anything with the unit tests

I looked it over and incorporated parts of it when I catkinized the whole pr2_common stack, which is now released into Hydro.