Removed bogus Coproduct refinement.
Use fundep materialization. Minor cleanups. Fixes #106. Fixes #108.
Merge commit 'cba50b6465df1a96665b00597f2b8efcf18ed10c' into scala-2.10.x

Conflicts:
	core/src/main/scala/shapeless/generic.scala
Merge branch 'master' into scala-2.10.x

Conflicts:
	core/src/main/scala/shapeless/generic.scala