Added pictures to game rules overview.

Map view icons are currently hotlinks to the repository. Closes Starstrider42/RemoteTech#10.
Added pictures to Flight Computer guide.

Note: The attitude control section does not match how the game behaves, particularly with respect to the TGT attitude mode. I'm assuming that the behavior described in the guide is intended, and that the unusual behavior of TGT mode is a bug; see RemoteTechnologiesGroup/RemoteTech#69.
Fixed errors in re-entry tutorial.
Tidied up documentation for 1.4.0 release.
Wrote comsat tutorial.

Also fixed remaining tech links, and corrected some mistakes about the modified time quadrant.
Wrote omni network tutorial.

Made corrections to satellite design and KEO tutorials. Gave Elan proper credit for coming up with multi-satellite launchers.
Removed cluster launcher from omni tutorial until RemoteTechnologiesGroup/RemoteTech#76 is resolved.
Forgot to run spell checker.
Stupid Github Jekyll, can't parse something local Jekyll can.
Formatting changes and one 1.4.0-related correction.
Fixed formatting error in constellation tutorials. Added warning.
Clarified wording to address frequently asked questions on the forum.
Updated banner links. Removed "Donate" button.
Updated credits for 1.4.0.
Added title to API page to prevent confusion.
Added skeleton framework for API guide.

@Cilph, @erendrake: any work on the guide should use this as the starting point.
Documented all RemoteTech settings except for `GroundStations`.
Made tutorials prettier.
Reformatted settings guide.

@Cilph, I think I understand everything in the options file except for the ground station Guid. Does this field have any requirements other than uniqueness?
Dummy commit

Trying to unblock site compilation