For logged-out users only.

Set up CacheManager as a Singleton.

Fixes various issues with showing/hiding/AJAX operations.

Filtered due to lack of support in MySQL < 5.5.3.

do not allow user to post the duplicate question once more time . It
checks the last 5 questions and compares with the current one . If any
of them appears to be same the user will be warned and the question will
not be posted
Fixes - #309

it is not required to loop through the other posts once the matched post
found

This fix checks for the question url . If it does not match with the
current URL then redirect to the correct one