Adding support for cm900 and opencm904 boards (robotis)

Signed-off-by: Grégoire Passault <g.passault@gmail.com>
Removing redundant defines (see #85)

Signed-off-by: Grégoire Passault <g.passault@gmail.com>
Merge pull request #85 from Gregwar/robotis

Adding support for cm900 and opencm904 boards (robotis)