Link validation and make test

 - HTML Validator now checks for links
 - External link results are stored in bin/validator/cache
 - bin/validate runs the validator with all htmls files
  - it also generates a temporary webcam.jpeg
 - make test -> bin/validate
Fixes to validator errors
Remove query string and fragments from uri checks
Add blockquote as a valid tag
Correct handling of realtive path names
Add a todo list