Fixed the bug
Version : 2.0
Date : 2014-7-30 19:34:06
Signed-off-by: jssoscar
Changelog : . Fixed the bug when num_edge_entry equal 0
	    . Optimize the code
Replace the "offset" parameter with "toolTipOffset"

Version： 2.3
Date： 2014-8-4 16:46:31
Changelog: . Replace the "offset" parameter with "toolTipOffset"
	   . Fixed the bug when gennerate the tooltip

Signed-off-by: jssoscar