Make it easier for apps using py to override configuration

[oubiwann]

The best solution for this might be to convert the LFE code to accept state data in each call, initialized in the app. At that point, any other app could start up the LFE py app with a different initial state (including config data).

For instance, right now it is difficult for lsci to override the log level of py from the lsci app. Perhaps more importantly, lsci can't control the number of ErlPort Python servers that py starts up (though it can create more dynamically via (py:add-server ...)). If lsci wants to change the type of Python server scheduler used, that is also cumbersome and can't be easily overridden right now.

[oubiwann]

lsci's got a work around for this now: lfeutre/lsci@a5c426a