CreateDatabaseActivity: Passing app task to next activity
Keepass.cs: added documentation on Activities and AppTasks
SearchActivity.cs: passing appTask to next activity, using ForwardResult to pass ActivityResult back to previous activity
FileSelectActivity: pass AppTask to CreateDatabaseActivity, Recreate instead of Start+Finish (to have correct handling of ActivityResults)
AppTask: bugfix for read-only dbs
CopyToClipboardService: Can handle time-out for additional strings copied to clipboard; can update the Keyboard data
added comments
minor changes
* EntryOutput is passed to CopyToClipboardService
* Modifications of EntryOutput are passed to plugins to enable actions on added fields
* PluginDatabase checks if Plugin is still installed and always updates the list of plugins (had an issue where a plugin had a request token but was not in pluginList)
* first version of QR plugin implemented
