implement QuotientRingElement._im_gens_()
FiniteStateMachine - LaTeX output in notebook

In #16020, graphs.setup_latex_preamble has been modified to include tikz
into the mathjax avoid list so that graphs can be rendered more easily in
the sage notebook.

This ticket does the same for finite_state_machine.setup_latex_preamble.
Automatically call setup_latex_preamble

As pointed out in http://trac.sagemath.org/ticket/16557#comment:2,
the graphs package automatically calls setup_latex_preamble when needed.
So we introduce the same mechanism for finite state machines.
This also removes setup_latex_preamble from the introductory documentation.
Moreover, setup_latex_preamble is decorated by @cached_function, as in
the graphs package.
Forgot to import cached_function
Python 2.7.8
Updated documentation.
Trac 16135: further documentation improvements
Trac #16557: FiniteStateMachine - LaTeX output in notebook

In #16020, {{{graphs.setup_latex_preamble}}} has been modified to
include tikz
into the mathjax avoid list so that graphs can be rendered more easily
in
the sage notebook.

This ticket does the same for
{{{finite_state_machine.setup_latex_preamble}}}.

Moreover, {{{finite_state_machine.setup_latex_preamble}}} is now loaded
automatically (as it is the case in the graphs module).

URL: http://trac.sagemath.org/16557
Reported by: cheuberg
Ticket author(s): Clemens Heuberger
Reviewer(s): Jean-Baptiste Priez
Trac #16135: Implement QuotientRingElement._im_gens_()

Ring homomorphisms whose domain is the fraction field of a quotient ring
don't work correctly:
{{{
sage: R.<x, y> = QQ[]
sage: K = R.quotient(x^2 - y^3).fraction_field()
sage: L.<t> = FunctionField(QQ)
sage: f = K.hom((t^3, t^2))
sage: f
Ring morphism:
  From: Fraction Field of Quotient of Multivariate Polynomial Ring in x,
y over Rational Field by the ideal (-y^3 + x^2)
  To:   Rational function field in t over Rational Field
  Defn: xbar |--> t^3
        ybar |--> t^2
sage: f(K.gens()[0])
Traceback (most recent call last):
...
NotImplementedError
}}}
This can be fixed by implementing `QuotientRingElement._im_gens_()`.

URL: http://trac.sagemath.org/16135
Reported by: pbruin
Ticket author(s): Peter Bruin
Reviewer(s): Luis Felipe Tabera Alonso
Trac #16648: Python 2.7.8

New tarball: http://boxen.math.washington.edu/home/vbraun/upstream/pytho
n-2.7.8.tar.gz

URL: http://trac.sagemath.org/16648
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): Emmanuel Charpentier