Development Branch Merge Request

This is a complete refactor of the exlibris-primo gem to use the [Savon gem](http://savonrb.com/) for SOAP interactions, provide access to all the Primo APIs, add documentation and tests.

It's not quite ready to merge yet, but we can definitely look at it.

@barnabyalter, @hab278 would like to do a code review of this tomorrow.