Merge pull request #11 from l0st3d/master

Signature tests
Extracted interface on Repository to assist testability of client code.
Merge pull request #12 from meboz/master

Extracted interface to assist testing
Mark IsCustomer and IsSupplier fields as readonly
Try and prevent 'nuget push' failures from failing the build
It works on my machine, but not on the build server apparently...
Replace test-cert.pfx with XeroApiNet-Sample.pfx, which is password protected
Move IRepository into separate .cs file
Mark more fields in Invoice as ReadOnly
Add ModelSerialiser.Serialise2 method
Switch off XeroApi.XmlSerializers.dll assembly generation
Add unit test for https://github.com/XeroAPI/XeroAPI.Net/issues/14
Increment version to v1.1.0.10
Add ShowInExpenseClaims prop in Account model
Add XeroApi.VBTests project
Fix Q48341, VB.Net linq query fails when using FieldExpression
Increment version to 1.1.0.11
Add test for filter 'GET Accounts' on new ShowInExpenseClaims property
Enable more methods to be used in WHERE filter (e.g. Name.Contains(""))
R#