[sailfish] Add components to the sailfish project.

Add the files in qml/ttrss/components/ to the list of other files in
the sailfish project.
License updates
[sailfish] Reworked the AboutPage

Also:
- Introduced a generic TextPage.qml to display the License and the
  Privacy Policy.
- Updated my contributor information. :)
[sailfish] Inlined the AboutItem
Fix warnings (QtCreator) and break overly long lines.
[sailfish] Refactoring: Moved "Add subscription" to function
[sailfish] Removed old MenuItems (comments)
[sailfish] VerticalScrollDecorator
[sailfish] variant is deprecated, use var instead

See http://qt-project.org/doc/qt-5/qml-variant.html
[sailfish] PushUpMenu for list of feeditems

Especially helpful for long lists.