Modify reads order in MCA by drag'n'drop

A read, selected in the Reads Name List, may be moved to another location in the reads list by drag'n'drop.
Scrolling is added, if necessary when the name is dragged.
Also, the visible area may be changed when the read is dragged to a new location.

One can also move a group of selected reads in the same manner.

Make sure the Undo/Redo works for this feature as well.