Cleaned up scan barcode component
Merge pull request #114 from mikemases/Scan_Barcode_Cleanup

Cleaned up scan barcode component
[#115] Enable parser for missing behaviours

Used pegjs to generate a PEG parser
Use that to process the requested missing handler name
Refactored handlers to return functions that can be applied
Refactored composite to work over a sequence of handlers
Refactored singular to take a particular handler
Merge pull request #132 from mattdenner/missing_behaviour_grammar

[#115] Enable parser for missing behaviours