Fixed #26 - axes now respect offsets properly and cleanup of other offset

[marzolfb]

Fix #26

• Axis component used on StockLine, SmoothLine, and Scatterplot charts now handles margin/offset properly
  • When changes are made to the margin options for these types of charts, charts should now display properly (where before offset would affect chart drawing area but not axes/gridlines)
• Modified Bar chart to fix display problems with labels along x-axis (removed 25 offset value)
• Removed unnecessary embedded G SVG grouping tag (to previously address offset handling) on StockLine & SmoothLine charts that was causing display problems
• Removed unnecessary embedded G SVG grouping tag (to previously address offset handling) on Tree chart