Merge pull request #255 from jeremygray/master

DOC: fine-tune style-guide for OpenHatch based on feedback
ENH: added the basic hooks for an ExpFile object in Builder Experiments

The ExpFile represents a psyexp file on disk and simply writes the code
represented by that experiment's Flow in the appropriate places in its
own experiment code.

As yet, this is untested and we need to work out how to specify filename
from the GUI and when to read in the file (e.g. should we reload from disk each
time we're asked to generate code?)
DOCS: Even joke tips should be semantically and gramatically correct
ENH: microphone.py now using sound.pyoSndServer

We can't have multiple pyo servers running at once. Deleted the
core.pyoServers list

Need to check whether the server is still being shut down properly when
this is done using __del__ (don't create extra pointers in microphone to
the pyoSndServer, just refer to sound.pyoSndServer!)

Removed the try...except...finally from the say_rgb demo
RF: remove microphone.switchOff()

but keep the function defn for now just for backwards compatibility