refactor much of the parsing code, get lang-agnostic test harness working
lighting up a few testcases
general improvements to compatability with reference impl
correctly handle default values
disallow empty values for short/long options that expect a value
update reference imcompatibilities in README
Merge branch 'reference-compatible' into friendly-api

Conflicts:
	System/Console/Docopt/Public.hs
	examples/naval_fate.USAGE.txt
finish previous merge to make API consistent with naming changes
compensate for ambiguous argument parsing (<angbracket> vs. UPPER styles) introduced in 8315abb