Minor improvement to how the proxy rewrites *.js files.
Minor improvement to how the proxy rewrites *.js files.

CMUBigLab/webanywhere,jbigham/webanywhere,CMUBigLab/webanywhere,CMUBigLab/webanywhere,CMUBigLab/webanywhere,jbigham/webanywhere,jbigham/webanywhere,jbigham/webanywhere