add support for unsigned int values import/export (close #2)
Rename ros_import into ros_publish, and ros_export into ros_subscribe.

The old names are kept for now, but will disappear in the
future.
Modify RosRobotModel to derive from sot::Dynamic
Merge remote-tracking branch 'origin/groovy' into groovy
Merge pull request #15 from bcoudrin/groovy

Modify RosRobotModel to derive from sot::Dynamic
Merge branch 'groovy'

Conflicts:
	CMakeLists.txt
	src/ros_publish.cpp