* Applied some code conventions, used more current language features which should improve readability and making it easier to re-factor / modify. Also fixed some typos in documentation.
* Changes based on PR conversation for the SystemInfo
* Some modifications due to conversations on the PR, especially I removed the FlagsAttribute on the BalloonFlags.
* Removed Silverlight targeting in code.
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CHG Removed version text from NuGet files.
CHG Replaced Tuple usage from SystemInfo by Point, which is also supported by .NET 3.5.
CHG Changelog and credits update.
Add extension point CustomPopupPosition to show Balloon on custom position.
AppBarInfo.WorkArea now return appbar workarea. Before it returns screen workarea.