Send ZIP and country only when available

Send ZIP and country code when ever available else don't send and
validation will be handled on endicia level.
Integrated shipping rates api #5846
Add mailpiece shape feature
Merge pull request #50 from sharoonthomas/develop

Add mailpiece shape feature
Make shipment respect mailpiece type too
Merge pull request #51 from sharoonthomas/develop

Make shipment respect mailpiece type too
Merge pull request #41 from tarunbhardwaj/rates-api

Integrated shipping rates api #5846
Merge pull request #45 from tarunbhardwaj/fix-zip-country-code

Send ZIP and country only when available
Provision to have custom name for mailclasses
Removed BaseTestCase from __init__.py.
BaseTestCase is needed to workout faulty inheritance.
Changed the endicia readonly test. - assertRaises has been
parameterized.
test_carrier and test_stock added and refactored to increase coverage.
Fixed test_endicia after pull and rebase on upstream.
Added endicia >= 0.5 requirement to setup.py.
Merge pull request #53 from VaticanCameos/endicia-test

Tests for readonly nature of endicia-mailclass.
Postage price should be calculated from PostagePrice node

* Added a fetch_endicia_postage_rate() to fetch price from lxml element