Fn 2 export Zemax fig windows to IPython Notebook

Minor change:
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Changed the interface of spiralSpot(hy,hx,....) to
spiralSpot(hx,hy,...). Although the previous interface matched MZDDE, it
is prone to mistakes as we use hx, hy everywhere else.

Major commit:
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Added function ipCaptureWindow() to capture and render currently open
graphic window into IPython Webnotebook or IPython Qtconsole. Also added
an example webnotebook and associated ZPL macros required for this
operation.