Fixed up a namespace pollution bug and some indentation

It wouldn't compile with gcc 4.7.1 due to a namspace conflict with the 'Left' and 'Right' from line 956 of src/Wt/Chart/WChart2DRenderer.C with the ones imported from WGlobal's "Side" enum.

I changed the Left, Right, Both chart enum to tLeft, tRight and tBoth.

Also my vim and github had tabs set to be 4 chars but the code was written with it as 8. As the code was using mixed tabs and spaces it looked gross, so I changed everything to spaces. :)