Catching HTTP 503 Service Unavailable
Adding support for linking payments to an invoice
Threading through initializer arguments
Adding discount line detail option to Line
Merge branch 'master' into catching_service_unavailable
Merge pull request #58 from harvesthq/linking_payments_to_invoice

Adding support for linking payments to an invoice
Merge pull request #59 from harvesthq/fixing_initialize_on_certain_models

Threading through initializer arguments
Merge pull request #60 from harvesthq/catching_service_unavailable

Raise Quickbooks::ServiceUnavailable upon 503 error
Merge branch 'discount_support' of git://github.com/harvesthq/quickbooks-ruby into harvesthq-discount_support

Conflicts:
	lib/quickbooks/model/line.rb
Added Contributors section
Adding support for adding taxes to invoices
Adding tests for tax rate and code services
Updating README
Merge pull request #62 from harvesthq/tax_support

TaxCode and TaxRate query support