Vamonos v2.1.0

• Fixed SVG text in Safari.
• Railroad Max Flow
• Fix firefox bugs: adding and dragging vertices
• Vamonos.error: if called in the algorithm, highlight where error was called in pseudocode
• vertices grow in width as their vertex-contents grow in length
• boruvka's algorithm - animate edge collapses
• graph - editableEdgeAttrs constructor arg
• graphdisplay - showVertexChanges option to turn off highlighting when vertices change
• graphdisplay - animateEdgeFlips: when an edge is about to removed
  and there is a new edge that goes from the old edge's target to its
  source, show a flippy animation.