This reverts merge request !5960

SugarCube repository moved from BitBucket to GitHub migrating from
Mercurial to Git. Hence the update for the guide.

Teach SugarCube to avoid cloning the state object when history size is
equal to 1

Added economy dev notes

2. When normalizing empty wombs, reset pregSource even if it's negative
3. Add TerminatePregnancy utility function to terminate a pregnancy with the appropriate postpartum length
4. Rework a whole bunch of places where pregnancy is terminated to use the appropriate functions and not set pregType/pregWeek/etc directly
5. Add postpartum delay when pregnancy is completely terminated by individually removing the last ovum from pregnancy inspection

Define save descriptions uniformly for the entire game, instead of using nonsense everywhere that's not the main page.
Patch Sugarcube to skip creating passage excerpts (which can be expensive) when descriptions are predefined.

Add some very terse build instructions for how to get Sugarcube to use FCHost's custom storage module.