Query renderer from sketch's code

[codeanticode]

The renderer is needed during the sketch build process because selecting the correct template to build a watch face project depends on whether the sketch uses the default renderer or the OpenGL renderer.

There was a function in an early version of the preprocessor in processing 4 that allowed to retrieve the renderer, but its now gone. The parsed render string is private in the PdeParseTreeListener and not available outside the class, so this requires either re-introducing an method to get the string, or implementing a custom parsing of the renderer in the mode itself.

@sampottinger @benfry let me know if you have any comments about this. Thank you!

[codeanticode]

Workaround at the moment with fa1441b

[codeanticode]

Fixed with Processing 4.0b8 and this commit 0c52678