Probabilities, probabilistics, and stochastics

[StoneCypher]

• Add the ability to seed the random generator at runtime #990
• Add the ability to seed the random generator from the constructor #991
• Define a loadable transition probability map #1244
• Define a mechanism for merging probability maps #1245
• Measure a machine history to determine the frequency of each exit #1246
• Measure a machine history to determine the likelihood that a state will ever be reached given a fixed starting point #1247
• Verify correct support for probability 0, probability false in random state transitions, tests #1248
• Large set of random walks to figure reachability (g'lawd this would take forever) #1249

This offers a basis for long term statistical reachability testing ("assert that this node is always at least 10% reachable")