Improved ICommandHandler task tracking
Refactored FeedManager and TrustManager to use DownloadFile task instead of WebClient for downloading XML files
Commands: Removed ActionTitle and GuiDelay
Removed DelayedGuiCommandHandler
ICommandHandler: Removed ShowProgressUI()

Activate UI implicitly
Renamed Disable/CloseProgressUI() to Disable/CloseUI()
Commands: Only call ICommandHandler.ShowSelections() when necessary
Updated NanoByte.Common
ManifestDigest.AvailableDigests: generate collection ahead-of-time instead of using yield iterator
Only force 0install.de SSL certificate  on pre-Windows 7 systems

Starting with Windows 7 the required CA is trusted by default. Calling NetUtils.TrustCertificates() is rather RAM intensive.
IpcStore: Turned ListAll() and ListAllTemp() into stubs
Publish: add stylesheet only to signed feeds