Improve Command Queue Documentation

        Issue #55

        Reviewed by Andre Loureiro.

        Make a better documentation for command queue in webcl-proxy.js and fix
        a loop in the same class that were executed one kernel twice in the same
        device.

        * webcl/resources/webcl-proxy.js
        * webcl/tests/webcl-kernel-result.html
Create test (instanceof) for new WebCLGL objects

    Issue #43