Constant-time string comparison in Phalcon\Security::checkHash()

Fix #1755
Test case for #1742
Make Phalcon\Logger\Adapter::commit() clear the queue
Fix #1683
Updated CHANGELOG
Regenerated build/
Code fixes for PHP 5.6-dev and 5.7-dev

(cherry picked from commit 105dee3cd5adc421cd3d60584233326d692f78d2)
Regenerated build/
Merge pull request #1758 from sjinks/1.2.5

[1.2.5] Bug fixes