FAST power schedule

[sears-s]

Set powerSchedule option to either:

constant (default):

• Configured to mimic original FLUFFI functionality
• Constant energy for each fuzz, incrementing towards maximum or decrementing if error occurs
• constantFuzz option is the starting energy (default: 50)
• maxFuzz option is the maximum energy (default: equal to constantFuzz)

or FAST:

• 
• minFuzz option is the minimum energy (default: 30)
• maxFuzz option is the maximum energy (default: 500)
• fastConstant option is the beta value in the above equation (default: 100)

Implementation notes:

• Column ChosenCounter added to interesting_testcases table which increments each time a testcase is chosen to be mutated
• GetTestcaseToMutateResponse message now includes rating, chosenCounter, and pathCounter

Relies on #275.