Laziness
Adapt unit test to lazy evaluation
Do not run plan unit tests for sequential
add lazy evaluation tests
Cleanup

remove unused argument
Plan, Fix offset computation

no longer assume partitions' first index is a multiple of the partition size
move offset computation in compute_partition
OpenMP: push colour iteration to python level
Plan: remove MPI specific properties
Plan: variable renaming
OpenMP: derive FakePlan from _GenericPlan
Make PPlan.echo __str__ method of _GenericPlan
We need a plan for any indirect loop

Conflicts:
	pyop2/openmp.py
Refactor base.ParLoop::compute

Orchestrate MPI operations in base.ParLoop instead of the backend subclasses
OpenMP, propagate changes from base.ParLoop::compute
Adapt unit tests to refactoring
Fix lazy execution on solve
Fix, add missing lazy evaluation dependencies
Fix, adv_diff_mpi demo stall
Fix, allocated size for Plan colouring arrays
CUDA, propagate changes from base.ParLoop::compute