initial model / service for Bill Entity
ignored .ruby-* for RVM environments
fixed Bill#txn_date
added Model::BaseReference for ReferenceType objects
refactored Bill LineItem into its own class
added Bill rspec
added BillPayment entity with spec
added BillPayment service
Merge pull request #18 from sequielo/entity-bill-payment

Added support for BillPayment
All reference types, e.g. Account#parent_ref are implemented via a first-class `BaseReference` instance.
Updating README for new reference setting syntax
add CompanyInfo model/service
Merge pull request #20 from seanxiesx/master

add CompanyInfo model/service
CompanyInfo is read-only so in the README mark any write operations as not-applicable
version bump for 0.0.4
Support for Vendor name entity
Merge pull request #21 from minimul/vendor

Support for Vendor name entity
accessors for CustomerMemo and PrivateNote in SalesReceipt
Merge pull request #22 from seanxiesx/master

accessors for CustomerMemo and PrivateNote in SalesReceipt
Support for Employee named entity