Update Version for maintenance release

Update the version number to "1.3.3" to indicate a new maintenance
release
Fix duplicateKiller function

Updated duplicateKiller function to use WP methods in lieu of MySQL
statements for finding and removing dupes.  Also references brafton_id,
rather than title, when tracking dupes down.
Close #5: Lower PHP version requirement to 5.2

Replaced anonymous function use for clients using PHP <= 5.2
Fix duplicateKiller function (again!)

Replaced original query with a "get_col" function call to prevent php
throwing warnings.
Add WP version check for duplicateKiller()

Cron lock resolution was fixed in WP 3.4 - this is a stopgap for older
WP installs until we find a better solution
Merge pull request #6 from ContentLEAD/dev-1.3.3

Merge changes for 1.3.3