webCLgl backend: fixed dynamic array inline into shader.
webCLgl backend: use `len(a)` and iterate `for i in range(len(a)):` loop over lists (inlined GLSL arrays)
webCLgl backend: fixed functions with no arguments.
webCLgl backend: fixed pure python typedef vars that use an attribute `a.x`
webCLgl backend: allow list slice on dynamic variables. new helper class `glsljit`
webCLgl backend: fixed dynamic attributes, js-mode needs glsljit code outside of wrapper function so that `this` can be bound properly.
webCLgl: regression test for dynamic return size
webCLgl: loop over array of arrays
webCLgl: support for integer arrays using Int16Array
updated GPU readme, fixed list slice, and new test call external method call from GPU code.