Fix null reference exception thrown when TextBlock text is null. (str…

…ide3d#84)

* Prevent TextBlock from throwing null reference exception when WrapText is set to true and the value of text is null. Fixes issue#82

[GitHub] changed abstract 'vvvv' to vvvv.org with link

[Build] PackageUpdateVersionTask: always update VersionSuffix (even i…

…f empty)