Revert "send all create requests using a POST request (untested, could break, ymmv etc...)"

This reverts commit 8652491295afe804668aa11bb2d9d93b4ebfece1.
fixing specs for changed put -> post
allowing parent to be nil for some Records (for testing purposes only).
switching fake application to nil in test
Take report response_xml.
Add associations to organization model
Add Xeroizer::GenericApplication.default_headers
Add tax components to tax rate
Unfreeze the gemspec's version string.

Avoids a "can't modify frozen String" error under older versions of Rubygems.
Added ExpenseClaim and Receipt models
Merge pull request #142 from sequielo/add-expense_claims-and-receipts-models

Added ExpenseClaim and Receipt models
Merge pull request #141 from fimmtiu/frozen-version-string

Unfreeze the gemspec's version string.
Merge pull request #140 from tradegecko/tax_components

Add tax components to tax rate
Merge pull request #139 from tradegecko/headers

Add Xeroizer::GenericApplication.default_headers
Merge pull request #131 from rdeshpande/master

Add phone and address associations to organization model
Merge pull request #127 from ilake/master

Take report response_xml.
Fix setting the 'Class' attribute on Accounts.

If you try to set the 'Class' attribute on an account, you'll get a
NoMethodError about the method "class=" not existing. This patch will try
the straight key name first, and if that fails, fall back to the field's
internal name ('account_class', in this case).
Don't use POST on endpoints that don't support it.
Added URL field to BankTransactions.
Merge pull request #147 from fimmtiu/add-url-to-bank-transactions

Added URL field to BankTransactions.