There are more elements in the dLbls spec that allow for customizations and formatting. For now, I am just implementing the basics. The DLbls class manages serialization of data labels showLeaderLines and leaderLines are not currently implemented
creates a new DLbls object
The chart type that is using this data lables instance. This affects the xml output as not all chart types support the same data label attributes.
The position of the data labels in the chart
Assigns the label postion for this data labels on this chart. Allowed positions are :bestFilt, :b, :ctr, :inBase, :inEnd, :l, :outEnd, :r and :t The default is :bestFit
Initialize all the values to false as Excel requires them to explicitly be disabled or all will show.
serializes the data labels
nills out d_lbl_pos and show_leader_lines as these attributes, while valid in the spec actually chrash excel for any chart type other than pie charts.