Introduce class Negatable
Rename the Negatable class to Neg
Make unary "-" use the Neg typeclass
Add support for the primitive prim__negFloat : Float -> Float
Rename float negation primitive for more uniformity
Add test for new float primitive prim__negFloat
Remove commented-out code.
CHANGELOG and doc updates for unary negation
Merge branch 'markuspf-negate'
sharingan