Clear temporary data, whether in cache or in transient
* Checks options tables for transients and delete them if appropriate
* Fires action hooks so themes, classes, plug-ins, shipping modules all can know when data needs to be cleared, or has been cleared
* Updated functions to use new clear data function rather than just wp_clear_cache
remember names of transients as they are set so we can clear them specifically
no mass flushing of WordPress cache
handles upgrade automatically by looking at database on first run
Merge pull request #1271 from JeffPyeBrook/pr-1251-clear-temporary-data

Clear temporary data, whether in cache or in transient