Update Cosima installation tutorial

[ndehio]

We installed the Cosima software on Ubuntu 16.04. Two dependencies were missing: sudo apt-get install libyaml-cpp-dev sudo apt-get install libgtest-dev

In addition, we use openjdk-8-jdk instead of openjdk-7-jdk. Please add this info to the installation tutorial.

There are also inconsistencies regarding different versions for Gazebo in the documentation sudo apt-get install gazebo7 sudo apt-get install libgazebo6-dev

[ndehio]

Finally, I also had to install: sudo apt-get install liburdfdom-dev

Please add it to the documentation webpage

[ndehio]

~Please add also to the installation tutorial that one might need another build-generator, which can be downloaded here: https://ci.cor-lab.org/job/build-generator-trunk/~

[xwavex]

@ndehio Thx! Looks like now we have everything updated on http://cogimon.github.io/software/gettingstarted.html