Merge pull request #328 from ufo-kit/rescale-image

Normalize image intensities
Don't use metaclasses for holding parameters
Don't pass redundant name to _install_parameter
Fix implicit state getting

The AccessorNotImplemented was caught correctly but caused
annoying log output.
Complete state tests
Remove bad state device test from fsm tests
Merge pull request #329 from ufo-kit/simplify-base

Simplify base
Fix IPython version check by gevent inputhook
Allow KeyboardInterrupt when gevent is enabled
Enable interrupting parameter accessors

for getters just silently exit and by setters allow the parametrizable to have
_cancel_param method for reverting the setter effect.
closes #330
Make devices abortable

which means bring them to some safe state.
Implement _abort methods in devices
Enable aborting all devices from a concert session
Add abort tests
Implement parameter setting cancellation in motors
Enable interrupting future's join and result
Add cancel_operation to futures for cancel cleanup
Add cancel_operation test
Cleanup after async parameter setter interruption

with proper cleanup.
Update the docs