Fixed two bugs in drawLine that causes it to never use WebGl

[Jesper-FRVR]

function drawLine(posA, posB, thickness=.1, color, useWebGL=glEnable)
{
const halfDelta = vec2((posB.x - posA.x)/2, (posB.y - posA.y)/2);
const size = vec2(thickness, halfDelta.length()*2);
drawRect(posA.add(halfDelta), size, color, halfDelta.angle(), useWebGL);
}

[Jesper-FRVR]

sry for not making a pull request ... but I've never figured it out :(

and thanks for a great library btw <3

[KilledByAPixel]

thanks, i got it fixed! the =glEnable isn't necessary because it will eventually default to that in drawTile, but the extra 0,s was definitely a bug.