update Scala copyright year to 2013
fix 5.1 regression in `one-of`

with the bytecode generator on and an input of unknown type, the input
was evaluated twice.  (and this actually changed the checksum of
Preferential Attachment, by altering the future of the RNG)

fixes #340
Merge remote-tracking branch 'origin/master' into core

Conflicts:
	docs/copyright.html