Constant-length dims, trying to simplify and improve compilation performance. Performance because geometrically worse.
Reasonable performance from dim-sets, finally.
Run-time performance has suffered, and the compiler crashes on 'newton * metre'.
Merge commit '0f0b922' into dim-sets

Conflicts:
	compile-bench/Bench.scala
	core/src/main/scala/Scalar.scala
	core/src/main/scala/Scunits.scala
	core/src/main/scala/Systems/SI.scala
	core/src/main/scala/Types/BaseQuantity.scala
	core/src/main/scala/Types/Integer.scala
	core/src/main/scala/Types/QList.scala
	core/src/main/scala/UnitM.scala
	test/src/main/scala/DimsTests.scala
Update breaking tests.
Improved runtime performance to within 15% of Doubles.