When building a PSE model, deadlock-state transitions don't get explicitly added.
Pre-compute mid-values of parameter bounds for region dividing.
Minor refactor.
Introduce DecompositionProcedure.
Minor code enhancements.
Support threshold synthesis.
Support max synthesis with the naive approach to determining the maximal lower probability bound.
Re-organise the PSE-related methods in prism.Prism.

Create auxiliary methods to aid code re-use.
Prefer the largest region for decomposing in threshold synthesis.
Refactor decomposition procedures.
Support min synthesis with the naive approach.
Minor code enhancements.
Add the Point class, BoxRegion.getPointSamples(), PSEModel.instantiate()
Explicit initialisation of decomposition procedures.
Support max synthesis with the sampling approach.
Fix leftovers: optimal -> optimising
Support min synthesis with the sampling approach.
Merge branch 'synthesis' into develop