Stacked Column chart formatting enhancements

[jgreene]

Here are a few things that I feel would be useful enhancements for the stacked column chart:

1. In series styles, replace current "Label Data Points" Yes/No dropdown options with "No/Top/Bottom/Left Side/Right Side/Alternating Sides" options to allow label text to fall above the line marking the top of the set (current implementation), below the top line, to the left or right or alternating between left and right.  Side labels reduce the need for #3 below and alternating side labels partially mitigate the need for #2.

2. If "Label Data Points" is turned on, allow an option to set a minimum threshold to display the labels.  In the current implementation the data point labels are placed on top of each other in cases where series with comparatively high volume are mixed with series with very low volume unless there is only one low volume series and it happens to be the last series in the set.  With alternating side labels from #1 above this would only be an issue if more than one consecutive low volume series was displayed.

3. Lighten default series colors or change default text color to white.  Black label text does not stand out or is unreadable against most of the default colors (dark blue, dark brown, etc.).