replace settings.json with settings.coffee
Dugway::Theme update for CoffeeScript settings
  - move settings files out of REQUIRED_FILES, into SETTINGS_FILES
  - add settings_file method (tells us which settings file is present/used)
  - add coffee_settings method (cleans/preps CoffeeScript for JSON.parse)
  - update settings method (parses .coffee or .json (backwards compatibility))
  - update files method (add settings_file to files array)
  - update valid? method (conditional error handling if no settings.coffee/json)
Update theme_spec for CoffeeScript settings support:
  - improve #settings test to verify non-nil & Hash (as described)
  - #settings verifies JSON.parse of coffee_settings, not settings.json
  - update #files test with base array & settings_file
  - update error strings
Update Dugway create for settings.coffee
  - call template on settings.coffee instead of settings.json
  - skip settings.coffee when copying source files (or we prompt for overwrite)
bump dugway version to 0.8.3