[BUG]: measureText not respecting ctx.direction

[ShaMan123]

I have encountered this bug when using ctx.direction = 'rtl' and ctx.textAlign = 'start' | 'end'

It is clear that the code fails to first resolve start/end textAlign and therefore executes as if direction is ltr.

node-canvas/src/CanvasRenderingContext2d.cc

Lines 2819 to 2832 in 1234a86

	double x_offset;
	switch (state->textAlignment) {
	case TEXT_ALIGNMENT_CENTER:
	x_offset = logical_rect.width / 2.;
	break;
	case TEXT_ALIGNMENT_END:
	case TEXT_ALIGNMENT_RIGHT:
	x_offset = logical_rect.width;
	break;
	case TEXT_ALIGNMENT_START:
	case TEXT_ALIGNMENT_LEFT:
	default:
	x_offset = 0.0;
	}

I am willing to PR.

[chearon]

I would love a PR, thank you.