fix imports (IntelliJ):
  - remove unused ones
  - organise alphabetically
  - organise in three sections: java, other, scala
  - reduce needeless complexity of relative imports
refactor isomorphism 4 extensibility + tests
move isomorphism code to iso directory
Ttrengthen isomorphism. 1million * improvement. Uses lazy data structure to explore possibilites. Calculates search space, and avoids searching through if too high.
minor changes & scalariformat
remove scalaz.Tree and use scalaz.EphemeralStream
replace recursive call with fold - it should remove increase of stack, but not sure how to test
split iso files, and other request by betehess
  - split files
  - add clearer documentation
  - case classes are immutable
  - node.fold(...)
  - other
Merge pull request #118 from read-write-web/topic/more-consistency

1 millon * improvement to isomorphism