Major add of unit tests for most commands. Some fixes resulting...

[guyacosta]

Major add of unit tests for most commands. Some fixes as a resulting benefit of these new tests to improve the core functionality and handle outlier behavior.

[guyacosta]

• Adds missing options for fileexlusionfilters to TagDiff and TagTest commands preventing ability to use with files under test, docs etc. folders
• Adds check for ability to write log file where requested
• Adds check for consoleverbosity = none and no output file specified for all i.e. no output anywhere
• Standardizes exit code names between tagdiff and tagtest; no values change
• Lowercases json tags fields for conformity
• Addresses count error in total matches by deducting tagcounters in preferences with includeAsMatch=false
• Adds unit tests and source files (early draft for now)