first attempt at passing task objects instead of task ids around
always provision a new worker when releasing one

Conflicts:
	metaopt/invoker/multiprocess.py
more pythonic value checking

Conflicts:
	metaopt/invoker/util/task_worker_db.py
make unit tests for multiprocess invoker work with status db
make examples work ... kind-a sort-a
run isort
Add simple timeout example
make examples work
raise stopped exception in MPI.invoke
use named parameters where ever possible
add Call to model, handle implications
cleaner parameter handling
fix duplicate calls to on_result
run isort
make child classes always overwrite parent / super classes
make code checkers happier
Fix some bugs and misbevhaviour in custom_optimize()

* The timeout is now cancelled when the optimization is already
  finished.

* Handle the case where the optimization finished without finding any
  paramters.

Conflicts:
	metaopt/core/main.py
quick fixes powered by landscape
fix a the None result bug for failing functions
make tests work by speeding up slow functions