DomainCanonicalizationValidator: Fixing get_no_301_description values
Reviewer: Fixing content_loaded method

'NoneType' object has no attribute '__getitem__'
Revert "Removed Limiter.matches obsolete method"

This reverts commit 7132b47e033b8dfae293eb98f6a56642f111c5ca.
Fixing limiter

Restoring deleted code
Add domain filter on ReviewPipelineHandler (fix #103)
Adapt reviews handlers to what WEB expects (fix #110)
Improving TestLimiter

Added test for get_limiters_for_domains method
Ignore surplus of active reviews per page (re #111)
Add support to search providers (fix #79)

To wrap up changes:

 * Default provider is just a bare-bones-search-in-mysql-using-like
 * Support ElasticSearch for a faster search
 * Create a console to setup, initialize and clear a search provider
 * Adjust *handlers*, models, tests, worker, etc. to changes
 * Create some config entries
 * Update docs (re #19)

Thanks @luizgpsantos for the support :+1: