Generate ROS2 library to avoid version incompatibility

[warnerjon12]

The original rosserial_arduino rebuilt the ROS library each time. This is helpful because it allows the project to be built with different (possibly incompatible) versions of ROS. It is also helpful to be able to build everything with catkin_make, which is why arduino-cmake was used. It seems arduino-cmake is inactive now, but my fork of arduino-cmake can be used and has been updated to work with the Teensy boards.