Camera uses XZY instead of XYZ

[DavJCosby]

According to the bevy-cheatbook,

• The X axis goes from left to right (+X points right).
• The Y axis goes from bottom to top (+Y points up).
• The Z axis goes from far to near (+Z points towards you, out of the screen).

I noticed, however, while using the flycam that the A & D keys slide the camera on the local X axis, W & D on the Z axis, and Shift & Space on the Y axis. Because of this, I ended up modeling my world in XZY space, which caused problems later down the line for me. Shouldn't Z be treated as the "up and down" axis, rather than Y, for the sake of consistency?

[sburris0]

Not a fan of this convention, but consistency is much more important. I'll make the change soon.

[sburris0]

Sorry, I forgot about this. I can add an xyz cargo feature, but I'm doubting bevy-cheatbook because adding a plane without specifying a rotation (see example) is parallel to what bevy_flycam would call the ground.

[oli-obk]

yea, I don't think this crate is doing anything wrong. See my changes in #41 which use the bevy functions for forward and right (and which work exactly like they did before if up is Vec::Y

If you want a different orientation, you can change what up is after my PR