Fix compilation on SBCL
Partially fix arglist introspection for SBCL
Fix compilation warning on SBCL
Fix compilation warnings on CCL
Port to CCL

CCL is rather strict about type annotations, e.g., about initargs that
don't conform exactly to the specified type.  This happens most
frequently when slots are initialized to NIL but NIL is not a member
of the specified type, or when an integer is used to initialize a slot
with floating-point type.  Common solutions for these problems are:

* Use a more permissive type declaration (usually (or null
  <previous-type>).
* Declare the initarg as required (using the REQUIRED-INITARG
  function from the UTILS package).
* Provide an initform of the correct type instead of NIL.

Which one is correct depends on the individual class; sometimes NIL is
used as a marker that denotes the absence of a useful value, at other
times the code supposes that the slot is properly initialized before
instances are used.  While I've tried to fix the type annotations and
initializations throughout the code, there are surely places where
I've overlooked something or chosen the wrong resolution.  Therefore
this commit is likely to be more buggy than the previous ones until we
have a test suite that covers more code paths.  Sorry about that.
Fix compilation on ECL

* Fix compilation errors on ECL introduced by the previous commit.
* Some examples work on ECL, however I have not found a reliable way
  to get arglist information in ECL, so examples that use function
  approximation don't work
.
Add some notes about porting to Bordeaux threads
Reformat code, add documentation

* Reformat the code to lines of 96 characters or less.  This makes it
  easier to read the source on github (and in editors that don't wrap
  lines).
* Add some documentation and start to make the format of the existing
  documentation more consistent.
* Do some minor cleanups of the code.
Consistently use :stream keyword instead of :str
Change type of learning rates to double-float

This avoids floating-point overflows on SBCL and is unlikely to cause
serious performance or space degradation.
Force output of progress printer

Also clean up code for tests.
Fix Concurrent ALisp

* Make Concurrent ALisp compile and run on Allegro CL again
Add larger test case for sequential ALisp
Remove ECL *.fas files
Add support for ABCL.

Also:
* Fix documentation in QE-Taxi example
* Force progress output in ALISP:EVALUATE
* Fix some formatting errors in the code
Add IGNORABLE declaration in MAKE-3PARTQ-FEATURIZER
Implement CHOICE-DIST for <GREEDY-POLICY>