improved handling of errors, esp. in .soy & .css:

- Soy and CSS (CLosure Stylesheets) processing now produce
  ResourceErrors and don't derail the process
- CSS processing uses the actual Closure Stylesheet processing classes,
  not the command line runner
- Closure Stylesheets should no longer complain about repeated CSS
  properties
Lighten some of the annoying and less helpful Closure warnings
Inline unknown script types with src attrs into HTML
Fix a null pointer error on empty HTML bodies
add directories to the watch to find new files