Finish processing library stuff

[hx2A]

Mostly done

[villares]

WOW!!!!!

[hx2A]

WOW!!!!!

This is a pretty neat feature. You'll be able to write code like this:

import py5_tools

py5_tools.processing.download_library("PeasyCam")

import py5

from peasy import PeasyCam

def setup():
    py5.size(500, 500, py5.P3D)
    PeasyCam(py5.get_current_sketch(), 500)


def draw():
    py5.background(128)
    py5.box(200)

and share it with others, without them having to fiddle with setting up the PeasyCam jars.

I'm going to do a release soon, maybe next week? It isn't a big release, will include this feature, setting jpype dependency to >=1.5.2, and using Processing 4.4.1 instead of my fork.

Shortly after this I will do something for JavaFX. The feature in this PR isn't enough for JavaFX to work painlessly but it is a step in the right direction.