Upgrade to CoffeeScript 4b4f6ac (post 1.6.2)

  * Use CoffeeScripts new `locationData` (and remove the homegrown
    line-counting.)
  * Use CoffeeScripts new error reporting for AST node operations (and
    remove the try-catch wrappers). This allows for resuming compilation
    after an error.
  * Improve tolerance for syntax errors by moving `error` symbol to
    `Body` production. (Better handling of indentation errors.)
  * Fix neighboring blocks with overlapping lines by limiting the
    length/position of `OUTDENT` tokens.
  * Improve/fix reporting for indentation errors.
  * Remove workaround for CS bug (since it is fixed now).
  * Update build process, project version and remove CS version from
    README and comments.