Problem in function jsdot_load_svg_shapes defined in shapes.js

When using XMLHttpRequest the file to load (shapes.svg) must be in the same folder as the html file. Instead, it should be in ../img/

This is a limitation in a workaround: if, when adding e.g. a marker-end using a url(), the browser would load the referenced file, then we wouldn't even need this function.

Note that using url(../img/shapes.svg#Arrow) works in FF when viewing a static svg (where the marker-end is not added by js but already resent).