Relase 1.3.9

For installation instructions see:

http://fricas.sourceforge.net/doc/INSTALL-bin.txt

Changes:

• Distributed binary includes support for jfricas.

• Construct of tagged unions by specifying tag.

• New category Hashable.

• AlgebraGivenByStructuralConstants now more general and
  has FreeModuleCategory.

• Rename 'escape' in Character to 'underscore'.

Bug fixes, in particular:

• Fixed power series expander for 'polylog' at 0.

• Fixed storing complex data, in particular streams in files.

• Fixed varius build problems, in particular build with
  sbcl-2.3.2 and newer.

• Main integrator no longer uses 'real'.