Updated CPTLegend to handle empty legends better and added a -description method.
Updated CPTLegend to handle empty legends better and added a -description method.

sureshdustrise/core-plot,kamalvenkat/core-plot,divyavamsee/core-plot,sureshdustrise/core-plot,divyavamsee/core-plot,eoinnorris/core-plot,tectronics/core-plot,zenXian/core-plot,LiDechao/core-plot,LiDechao/core-plot,LiDechao/core-plot,kamalvenkat/core-plot,eoinnorris/core-plot,tectronics/core-plot,zenXian/core-plot,tectronics/core-plot,eoinnorris/core-plot,divyavamsee/core-plot,tectronics/core-plot,zenXian/core-plot,kamalvenkat/core-plot,zenXian/core-plot,eoinnorris/core-plot,kamalvenkat/core-plot,sureshdustrise/core-plot,divyavamsee/core-plot,LiDechao/core-plot,sureshdustrise/core-plot