Add select icon
Add realization for SelectionDraggingToolAction
Add select action to ui
Add selectedNodes and checkSize method to GraphPanel
Put taskPanel and systemPanel inside JScrollPane
Change Point2D.Double to Point
Realization for NodeSelectionTool
Realization for NodeDraggingTool
Remove UnsupportedOperationException
Refactor NodeCreationTool
Add basic colors to COLORS
Add paint weigth for Node