Add an option to the setup dialog "Scale New Imported Images to Fit Canvas". Previou...

Add an option to the setup dialog "Scale New Imported Images to Fit Canvas".  Previously all imported images were resized to fill the canvas so smaller images were scaled more than bigger ones.  When importing PNG files with areas of transparent pixels around the ninja parts, silently ignore as many transparent pixels as possible without affecting the render.  This can be disabled by setting environment variable SYNFIG_DISABLE_CROP_IMPORTED_IMAGES.

git-svn-id: https://synfig.svn.sourceforge.net/svnroot/synfig@2193 1f10aa63-cdf2-0310-b900-c93c546f37ac