Update leading vertical offset to match processing
Update leading vertical offset to match processing

Text needs to have an additional vertical offset (based on vertical
alignment) when there are multiple lines.  Processing does this here:
https://github.com/processing/processing/blob/master/core/src/processing/core/PGraphics.java#L4610.
This commit brings p5's offset in line with processing's offset.

sakshamsaxena/p5.js,joecridge/p5.js,indefinit/p5.js,bomoko/p5.js,Jared-Sprague/p5.js,karenpeng/p5.js,mlarghydracept/p5.js,kadamwhite/p5.js,kadamwhite/p5.js,shiffman/p5.js,processing/p5.js,sakshamsaxena/p5.js,black-kite/p5.js,Jared-Sprague/p5.js,processing/p5.js,kennethdmiller3/p5.js,karenpeng/p5.js,joecridge/p5.js,mlarghydracept/p5.js,johnpasquarello/p5.js,dhowe/p5.js,limzykenneth/p5.js,nucliweb/p5.js,indefinit/p5.js,shiffman/p5.js,black-kite/p5.js,limzykenneth/p5.js,dhowe/p5.js,nucliweb/p5.js,kennethdmiller3/p5.js,bomoko/p5.js,johnpasquarello/p5.js