rename SuccessorList to NextNodeList
remove CRefactor subproject.

to be reintroduced as a separate project later.
(the current version here was outdated and maintained elsewhere in Andi's
fork)
minor refactoring for code readability

use Scala idioms getOrElseUpdate
renaming to avoid compiler error

name clash in two traits
fix typo
fix bug introduced in refactoring
infrastructure for all graphs and call graph comparison
extra tests -- for the test infrastructure