Trac #16917: deprecate cuspform_lseries() and modform_lseries()

We add a method lseries() to modular forms which creates the L-function
in both cases (cuspidal forms and eisenstein series), and we deprecate
the old two.

Part of this is unifying both methods which had very similar code but
were staring to diverge.
Trac #16917: fix a doctest
Remove usage of deprecated scipy.linalg.expm2 and expm3
add missing check for order
Merge remote-tracking branch 'origin/develop' into scipy_expm
add tolerance to doctest
fix alignment
trac #14019: Merged with beta6
trac #17181: Poset.__repr__ should mention the linear extension
trac #17181: Reviewer's remarks
Trac #16917: Deprecate cuspform_lseries() and modform_lseries()

From #11631:

  the name "cuspform_lseries" is bad, since f is already a cuspform, and
we use the name "lseries" in all other places (e.g., elliptic curves,
abelian varieties), so it is hard to find. In fact, I didn't even think
to look for cuspform_lseries, instead only finding this via lots of
grepping and reading source code.

The same applies to "modform_lseries".

The goal of this ticket is to add a method lseries() to modular forms
which creates the L-function in both cases, and to deprecate the old
two.

URL: http://trac.sagemath.org/16917
Reported by: tornaria
Ticket author(s): Gonzalo Tornaría
Reviewer(s): Michael Neururer, Nicolás Sirolli
Trac #17140: Remove usage of deprecated scipy.linalg.expm2 and expm3

{{{scipy.linalg.expm2}}} and {{{scipy.linalg.expm3}}} have been
deprecated in Scipy 0.13 [0] and will be removed in a later release.
Therefore remove both from sage.

[0] http://docs.scipy.org/doc/scipy-0.14.0/reference/release.0.13.0.html
#expm2-and-expm3

URL: http://trac.sagemath.org/17140
Reported by: aapitzsch
Ticket author(s): André Apitzsch
Reviewer(s): Jeroen Demeyer
Trac #17181: Poset.__repr__ should mention the linear extension

Hello everybody !

A poset with embedded linear extension can never be equal to a "simple
poset", and users are bound to wonder someday why two apparently equal
posets are not detected as such.

With this branch, this:
{{{
sage: Poset(digraphs.Path(5),linear_extension=True)
Finite poset containing 5 elements
}}}

becomes

{{{
sage: Poset(digraphs.Path(5),linear_extension=True)
Finite poset containing 5 elements with embedded linear extension
}}}

So that it is clearer that the Poset is 'not only a poset'.

URL: http://trac.sagemath.org/17181
Reported by: ncohen
Ticket author(s): Nathann Cohen
Reviewer(s): Nicolas Thiery