Merge pull request #73 from hawesie/hydro-devel

Removed strands_diagnostics to close #70
Remove obsolete diagnostics from launch.
removed empty log_extractor package
Make config_manager defaults path a parameter.
Update config_manager README.
Remove defaults folder.
added mongodb-dev as rosdep dependency
Not creating directory if not present.
Merge pull request #74 from cburbridge/hydro-devel

Move default parameter store. Closes #71
Renamed ros_datacentre to mongodb_store for to fix #69.