trac #15431: depends on #15287
trac #15431: depends on #15368
trac #15431 : Construction of TD(6,12)
Converted FreeAlgebra to inherit from CombinatrialFreeModule.
Fixes for coercion maps.
pyflakes cleanup of free_algebra.py.
Merge branch 'develop' into public/algebras/fix_free_algebras-14848

* develop: (121 commits)
  Updated Sage version to 6.2.beta5
  in docstring: added ``
  OSX 10.4 build fix
  Only accepts fields as input for change_ring
  FiniteStateMachine.determine_alphabets: one more small correction in docstring
  add definition
  use pydoc.pager on _sage_doc_unformatted instead
  FiniteStateMachine.determine_alphabets: corrected description of parameter reset
  Trac #13174: sagedoc.help() didn't discriminate cachedfuncs from funcs
  trac #15951 correct one raise statement towards python3
  Added destruction of pool in parallel_iter
  separate absolute from local (implicit relative) imports
  microfixes
  Added global options to rigged configurations to improve printing.
  Trac 13609: fix symbolic expression auto evaluation when content is in GF(2^k)
  Trac 13048: fixed division without remainder for polynomials over QQbar
  allow Singular to build with recent versions of Xcode
  removed k from init
  remove the avoid section "Function" in the intial comment and implement a function are_mutually_orthogonal_latin_squares
  Do not forget to define ambient_field before computing its algebraic closure.
  ...
trac #15431: rebase on updated #15287
(Hack) Fix for making FreeAlgebraElement work as a base ring for matrices.
Added variables() method to free module elements.
Merge branch 'develop' into public/algebras/fix_free_algebras-14848

* develop: (155 commits)
  Updated Sage version to 6.2.beta6
  32-bit fix
  typo fixing
  fix int/long doctest
  trac #16032: These matrices should be sparse
  trac 16032: This can be simplified... :-P
  Correct typo in sage/symbolic/ring.pyx.
  Put comment in the code and add more examples.
  trac #16032: reviewer's remarks
  FiniteStateMachine.__add__ is the same as __or__
  trac #16032: Bug in IncidenceStructure.dual_design
  final edits
  more changes -- please check if I got your algorithm right, Travis
  Review changes from Ben.
  further optimizations
  Fixed KR doctest and documentation of q_dimension.
  Fixes for q-dims for general highest weight crystals.
  more optimizations
  Partial work for general HW crystals.
  Review changes and (minor) optimizations.
  ...

Conflicts:
	src/sage/algebras/free_algebra.py
trac #15431: rebase on 6.2.beta6
trac #15431: Reviewer's remarks
trac #15431: Reviewer's remark II
trac #15431: remove old todo
transducers.add, transducers.sub: New transducers
Merge branch 'fsm/operator_transducers' into fsm/cartesian-product-intersection-additional-example
Transducer.cartesian_product: Additional Example (01-blocks minus 10-blocks)
transducers._operator: latex in Docstring corrected
trac #15431: Back to the standard definition of TD