checking in configuration for bwi-update-tool
testing tool by adding random apt package
Revert "testing tool by adding random apt package"

This reverts commit 0730ceb83a1c72f2a431482d8cf1676ef4720772.
system config now resolves the user config
checked in missing python packages from config. see utexas-bwi/bwi-update/#4
added depthimage-to-laserscan to system configuration
turned gazebo into a generic workspace, let vcstools handle all the mercurial stuff
added a rw variant of user config