Documentation and Travis CI configuration.

This release is very minor, but it adds some more documentation and has a working configuration for Travis CI. It also fixes a minor issue with Allegro CL (inlining can't be forced, so that test is skipped if it doesn't work). It's now tested on all those Common Lisp implementations except CMUCL (though only for lack of trying and the missing CIM part, so it won't happen automatically any time soon).

Initial release, basic functionality.

This is the first version I'm mostly happy with. Function rebinding is available, a somewhat nice syntax and enough tests to be sure it works.