updates datatips attributes
updates datatips specs
adds datatips normalizer and specs
runs ant graphicstests
first version of datatips code, needs to be debugged
updates positioning of datatips
datatips content is populated with proper values
adds first implementation of removing existing datatips
abstracts process of removing datatips
adds mark and remove approach to handling existing datatips
cleans up core code for datatips
cleans up event code for datatips
moves arrowLength onto the datatipsData object
datatips aren't drawn if plot is a ConstantPlot
lintifies
graph mousedown handler properly handles mousedown events on datatips