Merge pull request #75 from pal-robotics/fix-linking

Link controllers to catkin libraries
Added package for diff_drive_controller.
Had to create a modified version of CMakeLists.txt for qt creator to work, will remove later.
Added odom message type + fixed loading problems of plugin.
Added parameter and simple urdf parsing and realtime odometry publisher.
Added subscriber + real time stuff for cmd_vel subscription. Robot moves with joystick.
Fixed speed problems.
Added Odometry class refactored from old code. Updated manifest for dependencies.
Added odometry publishing to controller. Needs test with navigation.
Added tf publishing. The behaviour is not as expected, have to investigate.
Cleaning up/refactoring code
Moved static member to field
Moved ROS_INFO-s to ROS_DEBUG or removed. Added typedef for iterator type.
Fixed tf publishing error. Separated and minimized codes which are using locks.
Added publish rate param + handling.
Removed inlines and changed prefix _ to postfix _ for member fields.
Moved odometry computation into odometry class.
Moved getLeafNamespace function inline.
Removed copy constructor, assignment op, operator= since they were the same as the default.
Removed unnecessary linear_ and angular_ fields.
Made a few variables local.