feature:save-panel : reuse textfield css
Merged
Issue#145 : Hide highlighted pixel

+ BaseTool : added new method hideHighlightedPixel
+ DrawingController : mousemove event plugged on mousenter
  and unplugged on mouseleave
+ DrawingController : tool.hideHighlightPixel called on mouseleave and
  when switching the current tool to active (i.e. when user starts
  clicking)