added exception reporting for tasks in IDESolver
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!
initial draft of BiDi Solver
more advances on BiDi Solver
Merge branch 'develop' into forks/java-fw-bw
updated initialSeeds to include source statement
made process* methods protected
extracting method submitInitialSeeds to allow submission without having to wait
added support for debug name
removed unused import
BiDiSolver: support for debug name and simultaneous submission of both analyses
finalized (?) logic for bidi solver
make "propagate" protected
removed superfluous type parameter from PathEdge
Merge branch 'develop' into forks/java-fw-bw

Conflicts:
	src/heros/solver/IDESolver.java
changed signature of "propagate" to include original call site for return and call flows

modified bidi solver to changed attached source statement on return
toString
don't forget to clear pause list un unpause
improved and simplified handling of unbalanced problems:
we now just propagate up the call stack in an unbalanced way if for the very flow fact we are looking at there
was no incoming flow observed earlier
further fix for followReturnPastSeeds:
regarding Steven's earlier fix we now follow a different strategy…
we propagate upwards in an unbalanced way only such facts that originate from ZERO