Previously, document.mouse{enter,leave} was used for that. This
has the disadvantage that is doesn't work when the browser is
in fullscreen mode (at least, in Chromium), because the mouse
can no longer leave the document.
With this commit, mousemove is used to switch to fullscreen
in the photo view after the user has not moved the mouse for
some time. It is left again, if the user moves the mouse.
- Sidebar now visible along content
- Interact with the content while the sidebar stays open
- Fixed "ctrl+a also selects the "about" tab #230"
- Sidebar redesign
- Own module for the sidebar
