memory improvement: do not store implicit TOP values
bugfix: when propagating inside out into a caller that was not yet processed we need to create a summary edge starting at ZERO, not at the callee's flow fact!
Merge commit '987a7a4cd3a22d19845fd59885bfd25170798fe7' into develop
Merge branch 'develop' of git://github.com/Sable/heros into develop
changing initialization of analysis such that initialSeeds not is a mapping from units to initial data-flow facts at these units

this is a breaking change, but the class DefaultSeeds can be used to easily convert a set of units (old format) into a default map that should work for current clients

the change was implemented to permit subtypes of IFDSTabulationProblem to overwrite facts at seeds in a convenient way
Merge branch 'develop' of git://github.com/Sable/heros into develop