media: move "Update library" and "Stop scanning" out of the context menu
[confluence] add "Update library" and "Stop scanning" to sidebar
media: move "Now playing..." out of the context menu
[confluence] add "Now playing..." to sidebar player controls
CFileItem: add IsLibraryFolder()
video: fix "Set content" showing for library folders (genres etc.)
CFileItem: extend GetVideoContentType() to detect movie sets
CVideoDatabase: refactor SetDetail() into SetSingleValue()
DatabaseUtils: add GetField() and MediaTypeFromVideoContentType()
CVideoDatabase: add SetSingleValue() overloads
media: move "Edit title" context menu entry under new "Manage ..." entry
video: move "Link movie to tvshow" and "Remove link to tvshow" context menu entries under new "Manage ..." entry
video: move "Manage movie set" context menu entry under new "Manage ..." entry
video: move "Mark as watched/unwatched" context menu entry under new "Manage ..." entry
video: move "Remove episode bookmark" context menu entry under new "Manage ..." entry
video: move "Stack" toggle to settings
CGUIWindowVideoBase: remove unused CONTROL_BTNSCAN
video: move "Flatten" toggle to settings
video: add "Edit sort title" to "Manage ..." context menu entry
[ffmpeg] - backport - avio: Add an internal function for reading without copying

As long as there is enough contiguous data in the avio buffer,
just return a pointer to it instead of copying it to the caller
provided buffer.

Signed-off-by: Martin Storsjö <martin@martin.st>