Updates to ROS indigo until mid November 2015 

Updates to ROS indigo in October 2015

Added gst-plugins-good to DEPENDS line

Some of the gst-plugins-good modules were missing to setup a cam for some basic scenarios/tutorials. I added it so they'll be added to the default build set.

minor improvements to documentation and environment variables

README.md: use same installation guide for hydro and indigo (resolves…

As the installation guide for hydro and indigo only differs in
small details, the same wiki page is used for the hydro and indigo
distribution.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>

Updates to ROS indigo in August 2015

catkin: drop catkin_find from package (resolves #351)

catkin-runtime: including catkin_find (resolves #349)