Benchmark SQL backend

This is a commit for test purpose only.
Correct previous commit
Harder benchmark
Benchmark working
Add view table

See RFF 4
Add inc/views.php to handle view system

Start with parsing function (for words and rules)
First view to sql function.

It does not handle virtual tags yet.
And code is ugly!
Add virtual tags $all and $pubDate in views

But SQL query is bad. I must redesign it.
Fix rule2sql queries
Tests first working view!
Begin view integration
Integrate view system.

_home view is diplayed on home page. So read entries are not displayed for example.
The view system needs more tests.
Merge branch 'feature_views'