Added Functor instances for EdgeType In/Out; renamed in/out methods to inE/outE; added in/out methods for combo .out.map{ _.target }
Removed commented code; some experiments with composing edges
Merge branch 'feature/composition'

Conflicts:
	build.sbt
	src/main/scala/ohnosequences/scarph/EdgeType.scala
	src/main/scala/ohnosequences/scarph/Vertex.scala