Fix Issue #707 Set size of R graphics by defining a new function in the beaker module where you can give all the options to the SVG renderer (including width and height).  This introduces a complication which is you cannot access these options until they are defined, and our normal evaluation path does SVG setup, so I had to add an option to the evaluate REST call for "init" evaluations that do not do all the wrapping and output capture that normal user evaluation does
Merge pull request #725 from twosigma/spot/707

Fix Issue #707 Set size of R graphics by defining a new function in the ...