Add overloads of Select and Then for continuation actions
Use Select and Then in additional locations where appropriate
Update TestHelpers to show request headers as well as response headers
Allow providers to override the ContentType property (fixes #372)
Merge pull request #373 from sharwell/fix-372

Allow providers to override the ContentType property (fixes #372)
Merge pull request #374 from sharwell/SelectThen

Extend supported use cases for Select and Then extensions
Merge pull request #375 from sharwell/TestsShowRequestHeaders

Update TestHelpers to show request headers as well as response headers
Fix documentation reference not resolving
Fix _diskConfiguration field assignment
Merge pull request #376 from sharwell/MinorIssues

Minor issues
Cloud Images checkpoint
checkpoint
Implement most remaining methods
Improved object model for image tasks
Simplify constructors in UserImagesTests
Further work on implementing, documenting, and testing the IImageService
Extract unit test helper method GetUnitTestImageAsync
Add test for ListTasks and GetTask
Images updates

* Support image and image member filtering
* Updated documentation
* Improved integration testing
Initial implementation of IImageService.UpdateImageAsync