Violin Configuration Options - Initial

[Daniel Marsh-Patrick]

Add the following options for the violin portion of the plot:

• Stroke width
• Inner padding (range 0% - 50%), which will use from 100% - 50% of the range band for the violin plot width

[Daniel Marsh-Patrick]

#24: Added inner padding calculation and rendering, plus number range validation; changed stored width default to 2 (looks more "Power BI"). Resolves #24

→ <<cset c37baaa22ba8>>

[Daniel Marsh-Patrick]

Issue #20 was marked as a duplicate of this issue.