Update JSXGraph to 0.97

Please update JSXGraph to 0.97.

Sources:

 * jsxgraphcore.min.js: https://github.com/jsxgraph/jsxgraph/blob/RELEASE-0.97/distrib/jsxgraphcore.js
 * The *Reader.min.js files are Uglify2js'd versions of their counterparts in https://github.com/jsxgraph/jsxgraph/tree/RELEASE-0.97/src/reader


Thanks!