SAT naming comments
Aileron logic improvements and logging to determine which souces were used
Merge branch 'master' of github.com:FlightDataServices/FlightDataAnalyzer
FIX: Dependency Tree now establishes now links nodes to the root which are requested and have predecessors but none of its predecessors are requested. i.e. If you only request a parameter which has other nodes depending upon it, it would not link it to the root.

Added print_tree to assist in visualising the tree structure without drawing it to a picture.
indent tree only recurses the inactive nodes by default to constrain the output to the nodes that are innactive and therefore of interest.
Label nodes as per their class name and those in HDF as "HDFNode"
raise_inoperable_required option to process_order supports raising exception when any of the requested parameters are not available. 
Improved the printing of inoperable nodes
indent tree test cases - forgot to commit with previous commit.
Configuration uses Flaperon signal in place of Ailerons
Aileron Left and Aileron Right now merge inboard (in preference) and outboard signals.
Aileron simplified to use just L and R signals.
Aileron now aligns and takes the average of the two signals to result in the roll moment.
Flaperon test case
Changes notes
Flap merging logic simplified to blend in all but the exceptional cases
Elevator missing can_operate method
Elevator missing can_operate method
Sort the inoperable parameter list
Flaperon sets self.array = None when no aileron settings found
More explanation and logging to AirspeedReferenceLookup
Merge branch 'master' of github.com:FlightDataServices/FlightDataAnalyzer

Conflicts:
	analysis_engine/derived_parameters.py
	tests/derived_parameters_test.py
FlapAngle fix for params missing "Angle" name