Request: add a createShader( String [] vertSrc, String [] fragSrc ) function like p5.js has

Created by: scudly

Now that we have multi-line strings, it is practical to include shader code directly in sketches (or even to construct them programmatically) rather than reading from an external file. The current publicly supported and documented loadShader() API only cleanly supports reading shaders from files. Ideally, we would also have a createShader( String[] fragSrc ) that infers the type and provides a vertex shader as the current loadShader() does.

Passing the source as an array of strings seems more general than taking it as a single, multi-line string and is trivial enough to express in code. It also matches the existing PShader constructors.