utilities/redstone: Create a central ASIC, and test.

Trying something new for collating wires.
redstone: Switch to Asic() for ASICs.
utilities/redstone: Add input-finding abilities to find_wire().

Doesn't pass tests because torch orientation is still fucked.
utilities/redstone: Fix if/elif to if/if for torches.

Haha, such a simple mistake, but so very obvious.
exocet: Remove trivial diffs from t.p.modules.
utilities/redstone: More wire stuff, and test.
tests: Test update_wires().

It works! Holy crap, it all works! Maybe now I can sleep.
utilities/geometry: Enable negative endpoints in gen_line_simple(), and test.

Reported by Varriount on IRC.
utilities/redstone, plugins/redstone: Change Circuit.update().

This permits side-effecty updates.
utilities/redstone: Improve update_wires(), and test.
redstone: Fix lever orientations and updating.

Gets us through the chain of execution in the switch and OR gate tests.
Merge branch 'asic'
README: There is a PPA for Twisted.

Thanks to Markus Majer for pointing that out.
utilities/redstone: Permit torches on top of plain blocks, and test.
tests: Test wires powering blocks underneath.
tests: Fix OR gate test to actually test an OR gate.
tests: Nuke pointless and unhelpful switch test.
plugins/redstone: Remove update_wires() and tests, add AND gate test.

Works perfectly, with no extra code required. This is a good sign!
blocks, plugins/blueprints: Add piston blocks and recipes.

Fixes #375.
exocet: Silence warnings on missing imports.

These almost universally aren't fatal since the resulting errors are caught in
bravo.plugin.