Catkinize package
Add instructions for compiling with ROS groovy
Add support for inspecting data contained in a bag

By parsing all message definitions in a bag, it's possible to provide
functionality similar to 'rosmsg show'.
- ros.bag.definition(msg_type) is equivalent to 'rosmsg show msg_type'
- ros.Bag.rawDefinition(msg_type) is equivalent to 'rosmsg show --raw msg_type'

Additionally, ros.Bag.info() now returns almost all of the information
returned by 'rosbag info'.

All of this functionality is implemented by a new class BagInfo which is
defined in parser.hpp.
Update mex_compile.sh for catkin build
Touchup matlab doc strings
Explicitly check error conditions when serializing constants

Instead of implicitly casting istringstream to bool, explicitly check that
the no errors occurred and the whole string was consumed.