split the gazebo osdeps
rename the package set, so far it is for flat_fish
remove unneeded (and bogus !) line defining the install prefix for sdformat

The proper definition would have been without the leading D
   pkg.define "CMAKE_INSTALL_PREFIX", "..."

However, one should never set CMAKE_INSTALL_PREFIX explicitly.
In any case, it is probably overriden by autobuild.
remove obsolete packages and replace them by the final plugin & orogen integration
use sdformat 2.2.0 from bitbucket instead of 2.0.1

2.0.1 is buggy, does not install its CMake config file to detect
version, which causes gazebo build to fail