Don't display invalid shipping choices when there is a USPS quote error
* capture error from XML
* save error for next time checkout page is rendered
* output error (using existing action hooks ) into checkout page
* clear saved errors prior to shipping being recalculated

**Note that this is a quick (but reasonable) fix and needs to be expanded on going forward.**
updated since in phpDoc
changed function name
maybe?????
updated phpDoc
removed unnecessary assignment
Merge pull request #1286 from JeffPyeBrook/pr-1259-invalid-zip-codes-usps

Don't display invalid shipping choices when there is a USPS quote error
Remove commented out cached rate in UPS.  Debug cruft.
When USPS does not get a proper international rate, break loop, rather than set rate to 0.
Some cleanup (already in 3.8.14.1) from PR #1286
Clear temporary data on version change
When admin pages are displayed the version number is checked.  If the version has changed since the last check the WordPress object cache and the WPeC transients are cleared.
Merge pull request #1291 from JeffPyeBrook/pr-1290-cache-flush-on-new-version

Clear temporary data on version change
Cleanup cache invalidation routine
Fix fatal error.
Return value of global when current users cart is requested
Avoids going to database multiple times and creating copies of the cart that can get out of sync
Return true when there is more than one shipping quote
wpsc_have_morethanone_shipping_quote returns true when there is more than one shipping quote
Merge pull request #1295 from JeffPyeBrook/pr-1294-current-user-cart-return-global

Return value of global when current users cart is requested
Merge pull request #1297 from JeffPyeBrook/pr-1296-return-true-when-more-than-one-quote

Return true when there is more than one shipping quote
Cleanup shipping.php helper.
Indentation
When shipping parameters don't allow quotes to be calculated clear old results
Prevents shipping quotes from old parmaters from being displayed
Merge pull request #1298 from JeffPyeBrook/pr-1293-dont-hold-on-to-invalid-quotes

When shipping parameters don't allow quotes to be calculated clear old results