Added H1 Heading validator

This validator is optional and is not a mandatory SEO
violation in the comum sense. That`s why it is not
added to local.conf`s VALIDATORS setting.
Refactoring DomainDetailsHandler

Removed unnecessary status_code_info method
Releasing 0.10.1
Next job: order by last_review_date
Releasing 0.10.2
Simplifying meta_tags validator tests.
Cosmetic changes on Metatags validation class
Addded meta description too big violation

Now the `MetaTagsValidator` validates for meta tags of
description kind that have a content bigger than 300 chars.
Removing unnecessary import
Worker: fixing release next job
LastModifiedFacter: Added category
Worker: Except wihtout raise
Worker: Except wihtout raise
Releasing 0.10.3
Violations: Filtering queries with review_is_active == True
Releasing 0.10.4
Review model: Refactoring save_review()

Removing unnecessary deadlock check
Refactoring HolmesWorker
removing per worker limits on do_work
Releasing 0.10.5