Merge pull request #30 from pglazkov/notify-data-error-info-adapter-m…

…emory-leak-fix

Implement `IDisposable` in `NotifyDataErrorInfoAdapter`

fix: Use `JetBrains.Annotations` packages instead of including sources

Fixes #25

Update version

Updated version and the assembly info.

Fixed: "Async rule locking up UI thread" (Issue: https://mvvmvalidati…

…on.codeplex.com/workitem/7)

Fixed a bug with an exception when calling ToString on a ValidationRe…

…sult object if the validation result doesn't contain any errors. https://mvvmvalidation.codeplex.com/workitem/6

Added ReSharper annotations and missing code contract.

Bumped version to 2.0. This is a release candidate.

Fixed indentations.