PEP8 spacing in library_test.py
Added TODO about whether we should keep KeyPointValue slices
library_test spacing
Removed unnecessary spacing in flight attribute Approaches
Merge branch 'master' of https://github.com/FlightDataServices/FlightDataAnalyzer
Added align_slices for re-aligning slices from one parameter to another.
Merge branch 'master' of https://github.com/FlightDataServices/FlightDataAnalyzer
Merge branch 'master' of https://github.com/FlightDataServices/FlightDataAnalyzer
Changed from ilsfreq to ils_freq to be consistent with the new ApproachNode.
Removed unused testing code.
Removed unused test code.
Renamed duplicate test names in library_test.
Added align_slices library function and tests.
FDR Approaches and Approach And Landing combined into ApproachNode

A new type of Node has been added to node.py for the Approaches node. All nodes and tests using either FDR Approaches or Approach And Landing have been changed over to using the new combined Approaches node. This allows aligning of approaches while including airport, runway and another specific information.
Fixed key_point_values.py conflict.
Spacing only.
Added error message for fixing loops in the dependency tree.
Moved approach_slices from being a private method into a function.
Fixed find_app_rwy to use the new ApproachNode.
Resolved minor conflict in key_point_values.py