Update to FriCAS 1.0.8

Notable changes (compared to version 1.0.7) include:

  - Improved version of guessing package.  It can now handle
    much larger problems than before.  Added ability to guess
    functional substitution (Mahler) equations.
  - Experimental support for build using CMU CL.
  - Various speed improvements including faster indexing for two
    dimensional arrays.
  - By default FriCAS build tries to use SBCL.
  - Building no longer require patch.

Bug fixes, in particular:

  - correct definition of random() for matrices
  - conditionals in .input files work again
  - Spad compiler now recognizes more types as equal
  - fixed problem with pattern-matching quote

(asau)