composite linter and style checker

 Pocket-lint has several notable features:
  * Provides a consistent report of issues raised by the subordinate checkers.
  * Alternate Reports can be written to change the report, or integrate
    the report into another application.
  * Supports checking of multiple source types
   * Python syntax and style
   * Python doctest style
   * XML/HTML style and entities
   * CSS style
   * JavaScript syntax and style
   * Plain text
  * Supports reporting
   * Python doctests
   * CSS
   * XML/HTML