Add documentation strings

[gheber]

Give (documentation ...) a chance!

I'm also thinking of compiling a small list of the most commonly used abbreviations in the code, e.g.,
CMBN -> CoMBiNation, CFFC -> CoeFFiCient, ... Maybe as an a-list?

(pairlis '(cmbn "combination") '(cffc "coefficient") ...)

[gheber]

combinations.lisp done.

[dimpase]

yes, it's a great idea to document their abbreviations.

[gheber]

I'll start with a wiki page and then add an A-LIST.

https://github.com/gheber/kenzo/wiki/Abbreviations

[gheber]

See 32c2ab2.

[gheber]

Maybe we should take a look at https://github.com/didierverna/declt . It's not going to replace the user's guide, but it might make a better API reference.

[gheber]

Use LISP-STAT-like documentation strings such as in commit c89b005.

[gheber]

I think we need both of them: documentation strings and iPython notebooks. Documentation strings
are the baseline and get you going when without the Handbook and iPython. It's less sophisticated than iPython notebooks, but that's no excuse for not having it.