Refactor handling of interruptions
Remove useless file
Refactor Solvers

- We now explicitly create them from SolverFactories
- SolveSAT/solve/solveWithModel/etc.. is not only available through the
  SimpleSolverAPI() wrapper.o
- Remove mostly unused/useless solvers
Drastic memory management for solvers during synthesis

- Free&Recreate solvers during synthesis. This avoids huge memory leaks
  due to Z3AST never being reclaimed thourough the entire synthesis
  process

- Add safeguard to catch Z3Solvers for which memory management is
  incomplete
Debug sections become implicit
Increase test timeout

This should prevent false-negatives on unpredictably slow veficiation
tests such as invalid/RedBlackTree.
Only check master, include Philippe's email
Minor renamings.