org-odt.el: Rescale a large images so that it fits in text area

org-odt.el: Rescale a large images so that it fits in text area

* contrib/lisp/org-odt.el (org-export-odt-max-image-size): New
variable.
(org-odt-image-size-from-file): Honor above variable.

Ivars Finvers <ifinvers@shaw.ca> says -
   One minor issue that I came across in using the ODT
exporter relates to the size of embedded images.  I often need
to include plots of simulation results in my documents.  These
plots can be larger than a normal page, which causes problems
in the text flow.  In LaTeX, I've grown used to being able to
automatically rescale a plot to match the maximum text width
of the document.  It would be useful to have such a feature
for the ODT exporter.