Handle boolean meta value in a more backwards compatible way
The shipping same as billing meta value can be stored in several different ways depending on the version of WPeC that saved it.  Added a utility function to convert an arbitrary value into a bool with just a little more intelligence than a cast or checking a non-empty string.
Merge pull request #1247 from JeffPyeBrook/pr-1246-shipping-same-as-billing-meta-test

Handle boolean meta value in a more backwards compatible way