1) semantic fix: unbalanced returns are associated with a caller-side zero fact as context (d1), not with an empty list of contexts. This allows us to distinguish whether we actually have no caller to which to return or whether we have an unconditional taint.

2) code merge from Reviser: Allowing jump functions to be deleted
made a method protected
added SLF4j to the build script and the eclipse dependency list
Updated version and removed Scala from build.sbt