Check if path exists before moving
Check if path exists before moving

fs.move() no longer throws an exception if the target exists
so check for it explicitly when the dialog is confirmed.

matthewbauer/tree-view,ALEXGUOQ/tree-view,jarig/tree-view,ayumi/tree-view,benjaminRomano/tree-view,jasonhinkle/tree-view,tomekwi/tree-view,thgaskell/tree-view,rajendrant/tree-view-remote,Galactix/tree-view,pombredanne/tree-view-1,samu/tree-view,laituan245/tree-view,atom/tree-view,learn-co/learn-ide-tree,cgrabowski/webgl-studio-tree-view,tbryant/tree-view