Adds base handler class and scenario autostart

[wip] added base Handler class that opens websocket and responds to 'ping'
commands
[wip] added autostarting scenario; but facing timing issue (need to wait
that all handlers are in place, thus the ping/pong stuff above
Refactoring with subsystem class

trying to clean up the mess a bit
Adds generic subsystem binary

Adding a generic way to add subsystems
Moved adc to analog namespace
[wip] Mass refactoring

Adds auto handler loading and configuration
Heavy refactoring still going

Should be done by now.
Added audio, video, image categories on the client side
Changed few tools and removed virtualenv stuff
|w00t| Griotte can boot and start everything

Init script starts scheduler which in turn starts all configured daemons
and autostart scenarios.
Pygame + fbcon has an issue where quitting image handler will freeze the
next invocation (set_mode is blocked until SIGINT happends...).