Overhaul the pi_info system:
Pin factories are now capable of generating pi_info themselves (although
currently they all just look up the revision and call pi_info with a
specific one).
PiGPIOPin will now return pi_info for the remote pi which can be
specified by parameter or implicitly by the environment vars.
Overvolted Pis should work properly no matter what (some argument over
whether the revision 7 or 8 chars in this case; both should work). Added
some minor tweaks for the new camera-capable Pi Zero
Finally, added a bunch of tests for pins.data
While the tests work well on a PC or Travis, the Pi (where I ought to be
running them!) has some issues with the timing tests. Need to relax the
tolerance of the "assert_states_and_times" method to 0.05 seconds
otherwise it periodically fails even on something reasonably quick like
a Pi 2 (less failures on a Pi 3 but still occasionally).
Also reduced default fps to 25; if the default timing occasionally fails
on a Pi 2 it's evidently too fast for a Pi 1 and shouldn't be the
default; 25 also doesn't look any different to me on a pulsing LED.
There's also a bunch of miscellaneous fixes in here; last minute typos
and chart re-gens for the 1.2 release.
Change MockPin (and MockPWMPin) to make them behave more like 'real' pins - fixes#206
Add new MockPin tests, and rework some of the existing ones
Incorporate #216
