Add compiler support for more OutputPort types

[jvesely]

Current status:

Mechanism:

• [x] RESULT
• [x] MECHANISM_VALUE
• [x] OWNER_VALUE

ProcessingMechanism:

• [x] MAX_ONE_HOT
• [x] MAX_INDICATOR
• [x] MAX_ABS_INDICATOR
• [ ] MEAN
• [ ] MEDIAN
• [ ] STANDARD_DEVIATION
• [ ] VARIANCE
• [x] MAX_VAL
• [ ] MAX_ABS_VAL
• [x] MAX_ABS_ONE_HOT
• [x] PROB

ObjectiveMechanism:

• [x] OUTCOME (needs test)

TransferMechanism:

• [x] COMBINE (needs test)

ComparatorMechanism

• [ ] SSE
• [ ] MSE