Font cache testing

This test makes sure that even though a large number of distinct font objects will be used, Processing.js switches over from full font object caching to initial-metrics-only caching when 50 fonts have been cached, turning off caching entirely once the metrics-only font cache hits 400 fonts.

The test is performed by having a sketch use a textSize(random(10,60)), which allows for 501 distinct font name/size pairs to be cached, due to font sizes being rounded to a single decimal value. As such even though one font is used, its possible size values 10.0, 10.1, ... , 59.9, 60.0 leads to 501 possible pairs.

caching:
cache size: