Determine queued status when fetching from database.
Simplify voting tooltips.

Move functionality to FileCacheDriver, strip down manager class

And always show Caching admin submenu

Closes #509

Updated for Travis CI links

Fixed php 5.3 Travis CI fail issue

Updated readme for sites info

Used ref from http://www.question2answer.org/sites.php

Travis CI failing for Q2A v18, issue with php 5.3, see below link for more detail
http://question2answer.org/qa/58152/travis-ci-failing-for-q2a-v18-issue-with-php-5-3

Pointed to correct build status png file.

Updated PHPMailer to v5.2.23 (from v5.2.14)

Fix Facebook login issue #510

@Scott, @pupi1985

This fix is written and verified by http://question2answer.org/qa/user/Dan+D. in below thread http://question2answer.org/qa/56966/facebook-login-stopped-working-its-not-even-working-your-site?show=56992#a56992
also see https://github.com/q2a/question2answer/issues/510

I'm just submitting code changes.

Please check line no 593 for currentUrl. 

Thanks to Q2A user Dan D, and Github users valan, iamdand, cksagherian for this patch.