added pause and resume commands to SimpleShell
this system enables a solution for active endstops demonstrated in the Smoothieboard ConfigSample
moved Pauser into Robot (implemented Modules should not be in libs)
renamed pause and resume commands to freeze and unfreeze
moved freeze and unfreeze commands into PauseButton
Merge pull request #413 from logxen/pausecmd

added freeze and unfreeze commands to PauseButton