Calculate mouseX, mouseY per series.  Fixes #80.
Calculate mouseX, mouseY per series.  Fixes #80.

HumbleSoftware/Flotr2,jessiejea/Flotr2,HumbleSoftware/Flotr2,jessiejea/Flotr2,RobertoMalatesta/Flotr2,alanponce/Flotr2,alanponce/Flotr2,nicgallardo/Flotr2,alanponce/Flotr2,beastlike/Flotr2,beastlike/Flotr2,nicgallardo/Flotr2,RobertoMalatesta/Flotr2,jessiejea/Flotr2,beastlike/Flotr2