Arbitrary Join count walkers solution

Possible solution for Arbitrary Join problem in pagination count
walkers:
https://groups.google.com/forum/#!topic/doctrine-user/rpPYCDNKOU8

Added a condition to test query component against  SelectStatement from
clause
 Root selection according other pagination tools

changed root selection in Walkers from looping queryComponents to using
$AST->fromClause as other walkers have
Added Tests for Arbitrary Join
fixed typos in tests
Updated Asset queries

Missing  braces and selected fields
CS Fixes
Changed calling $from[0] to using reset($from)

changed usage $from[0] according suggestion from @Ocramius  to use array
reset function
Merge pull request #1092 from birko/pagination-count-walker

[DDC-2794] Arbitrary Join count walkers solution