More reorganization of developer guide

Broke coding section into useful subsections
Add how to create a tutorial from a worksheet

Also some more minor reorganization
Add small detail about how to make linking work right
Reorder index
Merge branch 'ticket/17307' into ticket/17265
Unindent assumptions
Document --sh instead of -sh command line arguments
Merge branch 'develop' into makethemtuts
Slightly elaborate on sws2rst instructions
Merge remote-tracking branch 'origin/develop' into ticket/17265
Small changes to the documentation documentation
Trac #17265: Add info on making tutorials from worksheets

Sage-combinat has been adding tutorials to their own
[http://combinat.sagemath.org/doc/thematic_tutorials/index-sage-
combinat.html#thematic-tutorials-sage-combinat website] for quite some
time.  Others should know how to do this more easily from worksheets.

URL: http://trac.sagemath.org/17265
Reported by: kcrisman
Ticket author(s): sarah-marie belcastro, Karl-Dieter Crisman
Reviewer(s): Jeroen Demeyer