Blued a bit of text in `ScreenHowToPlay`.
Added texture fonts rendered from Orbitron.
New improved title screen parallax clouds.

Made in GIMP using the following techniques.

Making some opaque bluish clouds (as with the backdrop):

* Create a 4096 × 512 RGB image.
* Fill it using Filter/Render/Clouds/Solid Noise.
    * Randomize (or otherwise set seed)
    * Not turbulent
    * Tilable
    * X size 8, Y size 1 (4096:512 = 8:1)
    * Detail 5 (adjust to taste)
* Make it blue with Colors/Colorize (Hue 240, Saturation 60, Lightness 0).

Making some sparse bluish clouds (as with the forward layers):

* Create an opaque bluish clouds image with the instructions above.
* On the clouds layer, do Layer/Mask/Add Layer Mask.
    * No need to change the Initialize Layer Mask setting; it will be clobbered anyway.
* Generate another cloud image using Solid Noise (select a new seed if not Randomized).
* Darken the cloud image in the alpha mask to make the clouds more sparse.
    * Do Colors/Levels.
	* Change the Input Levels black point (left handle, should default to 0) to 128.
	    * Lower values should result in less sparseness.
	* Leave the Input Levels white point (right handle, should default to 255) at its current value.
	* Keep Gamma at 1.
	    * Fiddling with this affects the sharpness of the cloud edges. I didn't want that effect.
	* Output level defaults should be OK.
* Do Layer/Mask/Apply Layer Mask to make the effect permanent.
Added new sparse parallax clouds to How To Play.