Project View improvements

See: http://ugene.unipro.ru/forum/YaBB.pl?num=1406635338

The following improvements can be done:
1) There is a possibility to store documents in folders for a remote storage, but currently there is no possibility to create folders locally. It must be added. Also, it should be possible to manipulate all files in a folder (sort, unload?, etc).
2) Think of adding the possibility to change the documents order by dragging them.
3) Provide some sort of sorting mechanism. Sort files by default, when they are added to project (i.e. the added files).
4) Add a circular icon to sequences that are circular. Maybe, this should be clickable, so that the sequence can be set as circular/non-circular.