Real-time planning: mergeSolution()

[ge0ffrey]

ProblemFact changes are tedious to use: for every possible change, you need to write a custom problem fact change.

Alternatively allow this workflow:

• User submits a problem, solving start
• User makes changes on the original problem
• User submits the changed problem as a "solving merge"
• The solver solves the changed problem, but initializes it's values from the originally solved problem, as much as possible

Extra design requirements:

• Can a user accept a best solution event, to pin the decision?