Fix direction of X axis in Specification.adoc

[Squeakrats]

The +X axis points to the right.

[lexaknyazev]

With +Z pointing forward, +X points to the left (hence -X points to the right) since it's a right-handed coordinate system. Please see the inlined image.

[javagl]

Despite having followed that discussion, I just looked at the change and the spec and for a short moment thought: "Wait, shouldn't that really be +X in the text?"

The confusion could probably alleviated by using some sort of "Avatar" (instead of the BoomBox), maybe even with the hands labeled 'Left' and 'Right':

"Ah, yes, that's the left hand!"

[Squeakrats]

I originally interpreted forward as you would in image editing software.
"Bring To Front", "Send to Front", or "Bring Forward" will bring the shape to the front. That was what I thought "+Z as forward" was meaning to convey. From that perspective (the viewer perspective) right is still right.

After reading the response and re-reading the text I realized it was intended to be relative to the object, which probably makes more sense.