Implement extra flags for verbose error messages

[avidrucker]

• Add flag detection for --verbose and -v as a shorter alias to lcc.js, interpreter.js, and assembler.js
• Add boolean this.verboseModeOn to both assembler.js and interpreter.js
• Pass flags down from lcc.js
• Add if/else to helper function to avoid cluttering up where error messages are generated
• Refactor/analyze where/why different error reporting functions might be used (console.error() vs this.error(), etc.), and see if this can be made clear & consistent