Started to work on the AmpDecorator wrapper.
Added TCP Server for incoming marker.
Replaced Thread with Process.

This is necessary because the get_data from the underlying amp driver
might use C calls which don't release the GIL. In this case the Thread
which collects the data from the socket is paused and can therefore not
correctly timestamp the incoming markers. This is not the case for a
process which runs independently from the GIL.
Added calculation for sample number within block.
Added _debug_tcp_marker_timestamps

for debugging the latency between sending and receiving marker.
Modified get_data call according to new return value.
Merge branch 'feature/decorator'