[cmucl-imp] March snapshot

[Raymond Toy]

The March snapshot has been tagged and binaries will be uploaded soon.

The main changes are:

  * run-program accepts :element-type to specify the element type for
    the streams that are created.
  * Lisp-unit (a Lisp framework for testing) has been added as a
    contrib.  Use (require :lisp-unit) to compile and load it.
    Unlike asdf and defsystem, precompild fasls are not included.
  * Type derivation for log was not consistent with the values
    actually returned by log.  This is corrected now.
  * Double-double floats were missing the constants describing various
    limits such as least-positive-double-double-float.  These are
    added now.
  * When reading very small floats values, the reader will round to
    least-positive float if possible.  Otherwise an error is still
    signaled.

Ray