Move the attribute whitelist from the validation module to the validate-attributes rule.
Remove leftover attribute whitelist from the validation module.
Move the element validation whitelist from the validation module to the validate-elements rule.
Update the FAQs.
Add a config option to the duplicate-ids rule.
Add a config option to the inline-event-handlers rule.
Add a config option to the validate-element-location rule.
Merge branch 'rule-config'. Closes #30.
Update FAQs with CORS info for stylesheets.