Add a new named pipe to allow other processes to send python scripts
to fontforge for execution. This file is owned by and only writable by
the user. Also some new code to track the last active fontview and
charview to help code that needs context but does not explicitly track
it, for example, the code that runs a python script from the named
pipe wants to pass the active char to that script so it can perform
something on that char.
Merge pull request #1269 from monkeyiq/2013march/python-pipe

Add a new named pipe to allow other processes to send python scripts to fontforge for execution.