Add a summary of how to submit a pull request

Also add REP 137 reference.
Status of octomap releases
Moved status
fixing quotes
rqt_common_plugins) 0.2.16-0 for hydro. Status added.
releasing joystick_drivers 1.9.10 to groovy and hydro
Merge pull request #775 from jbohren-forks/master

releasing smach 1.3.0 to hydro
Merge pull request #768 from ros/readme_update

Add a summary of how to submit a pull request
adding maintainer status
Merge pull request #776 from jbohren-forks/joystick_drivers

releasing joystick_drivers 1.9.10 to groovy and hydro
add more timeouts for groovy and hydro
[hydro] remove version of joystick_drivers since the gbp does not contain a hydro release
re-adding joystick drivers to hydro
Merge pull request #777 from jbohren-forks/joystick_drivers

re-adding joystick drivers to hydro
Merge pull request #774 from 130s/master

rqt_common_plugins) 0.2.16-0 for hydro. Maintenance status added.
add test which generates cache to verify that released packages are fetchable
Merge remote-tracking branch 'upstream/master'
Moved status
Adding socrob-ros-pkg to documentation index for distro
Merge pull request #778 from joaocgreis/master

Adding socrob-ros-pkg to documentation index for distro