Merge pull request #4 from m4cx/develop

Enhencements and Refactoring
Add XmlSchemaClassGenerator
Download and generate classes for all APIs
Update XSDs
Fix SampleConsole/Program.cs to work with RealEstateItem
Remove empty MessagesExtensions.cs
Update RestSharp, Rx
Set version to 1.2
Updated NuGet release notes
Add Search resource
Add link and video stream attachment methods
Make Publish resource use PublishChannel (fixes #5)
Use XmlSchemaClassGenerator from NuGet
Move ImportExport resources into subfolder
Add search tests
Add XML comments to search classes
Add OAuth authentication
Update README.md
Merge remote-tracking branch 'remotes/origin/mganss-test' into develop

Conflicts:
	IS24RestApi.Tests/AttachmentTests.cs
	IS24RestApi.Tests/IS24RestApi.Tests.csproj
	IS24RestApi.Tests/RealEstateTests.cs
	IS24RestApi.Tests/packages.config
	IS24RestApi/AttachmentResource.cs
	IS24RestApi/IPublishResource.cs
	IS24RestApi/IS24Connection.cs
	IS24RestApi/IS24RestApi.csproj
	IS24RestApi/ImportExport/ContactResource.cs
	IS24RestApi/ImportExport/IAttachmentResource.cs
	IS24RestApi/ImportExport/PublishChannelResource.cs
	IS24RestApi/ImportExport/RealEstateResource.cs
	IS24RestApi/PublishResource.cs
	IS24RestApi/Types.generated.cs
	IS24RestApi/packages.config
	IS24RestApi/xsd/common/common-1.0.xsd
	SampleConsole/Program.cs
	SampleConsole/SampleConsole.csproj
	SampleConsole/packages.config
Update XSDs
Update XSDs