Unit test for motor control boards

[traversaro]

Was robotology/icub-main#64

Things to check:

• call to methods that are supposed to read from local buffers (and not from RPC) should be checked for the time spent in the call. This could also be a good example for adding some time related assert/check macros to RTF.

cc @randaz81 @francesco-romano @apaikan @lornat75 @barbalberto

[lornat75]

Ok in principle. The problem with time related tests is that they depends heavily on the load of the machine in which they run. In YARP when I added tests on thread scheduling I made them non-critical bc I found they could rightly fail if the machine was loaded.