Enhance customer meta API
Add filters for get/set customer meta functions to allow processing and virtualizing of customer meta
Add functions to check if customer ids have purchases, posts  or comments
Customer meta hardening

Added documentation describing customer profile implentation to customer.php

Added function to allow last active time to be set for users other than the current user.

Avoid deleting users that have posts, comments or purchases associated with thier user id.

Fill in purchase log user id field with temporary profile id when purchase is completed.

Adjusted the temporary profile delete processing and logic to eliminate unused temporary customer
profiles sooner.

Added filters paralleling what is available in WordPress for hooking customer meta CRUD operations.
It would be great to have these filters for ewach of our meta types.
added loop protection to deleteing temporary profiles
renamed a variable to be more useful
updated comment
comment and shitespace updates
extend interval for delete processing based on constant
comment and formatting updates.
Add instance of in place of is_a.
change delete customer profile in merge cart function to abondon customer profile.
added abondon customer profile that essentially marks a temporary profile as ready to delete.
In clean up cron make delete profile request via async post through ajax-admin.
Ensures that the compelte wordpress admin is loaded so that delete
processing can proceed without error.
replaced filter with action, and moved to close of function.
Makes it possible to call customer meta functions during filter
processing without creating infinite loop
Found a bug, fixed it.
removed duplicate line
bugfix.  parameters were swapped on a get call, fixed.
removed redundant get customer id call
bug fix.  temporary profile expires time was not being updated.
Check memory consumed processing
Added a memory consumed check to the the delete processing to take into account the amount of memory that is consumed by deleting users.
confirm customer id is valid integer
confirm wordpress user exists when validating customer cookie
Whitespace and code standard update.  No logic changes
whitespace updates