Used system color settings to color process name text as a tooltip.
Made compatiable with Windows, set axes background to system theme.

Processes which the user doesn't have permission to view the name of are
given the name "ACCESS DENIED".

wx.SYS_COLOR_BTNFACE is used to get the window color because
wx.SYS_COLOR_WINDOW returns white on certain systems, such as Windows.
Hid axes spines.

The only chart artists visible are the title, process wedges, and text.