A method to unset category initialisation
trac 12186 speedup of norm
Implement integration and division or power series.

Fix latex of multivariate power series (missing {} in printing of exponent order)
trac #14814 review patch (minor details)
trac #14814: review patch
Trac #15564: Doc misformatting in toric varieties

While building the docs, I noticed
{{{
[schemes  ] /home/king/Sage/git/sage/local/lib/python2.7/site-
packages/sage/schemes/toric/library.py:docstring of
sage.schemes.toric.library.ToricVarietyFactory.torus:7: WARNING: Inline
interpreted text or phrase reference start-string without end-string.
}}}

URL: http://trac.sagemath.org/15564
Reported by: SimonKing
Ticket author(s): Simon King
Reviewer(s): Volker Braun
Trac #15566: The -sync-build option is broken

URL: http://trac.sagemath.org/15566
Reported by: vbraun
Ticket author(s): Volker Braun
Reviewer(s): Nathann Cohen
Trac #12186: Faster norm calculations

Using a relative norm calculation is far slower than using an absolute
norm calculation. The first should therefore be avoided if possible.
What is needed is a patch that avoids using relative norm calculations
when they are not necessary. The problem is well summarized in the
following example:

{{{
sage: K1.<a1> = CyclotomicField(11)
sage: K2.<a2> = K1.extension(x!^2 - 3)
sage: K3.<a3> = K2.extension(x!^2 + 1)
sage: t=a1+6*a2+a3*a1
sage: %time t.norm()
CPU times: user 0.10 s, sys: 0.00 s, total: 0.10 s
Wall time: 0.11 s
46593592840125350650995659797233874763776
sage: %time t.norm(QQ)
CPU times: user 2.11 s, sys: 0.01 s, total: 2.12 s
Wall time: 2.23 s
46593592840125350650995659797233874763776
}}}

URL: http://trac.sagemath.org/12186
Reported by: MvanBeek
Ticket author(s): Monique van Beek
Reviewer(s): Volker Braun, Frédéric Chapoton
Trac #15234: Make it possible to revert category initialisation

I am introdicing a method
`sage.structure.parent.Parent._unset_category()` that changes the class
into the "category-free" base class and resets the `._category` cdef
attribute to None.

In this way, it is possible to redo a wrong initialisation or refinement
of category.

The idea for creating this method arose in #15229: It is possible to do
`R = IntegerModRing(15, category=Fields())`, and then `R` will believe
that it is a field, and will actually be initialised in a sub-category
of `Fields()`. With the new method, it would be possible to revert the
wrong category initialisation and re-initialise it correctly.

Disclaimer:

- I do not think that we should ''automatically'' apply this method,
e.g., if `R.is_field(proof=True)` finds out that the modulus actually
isn't prime. Its use should be reserved to expert users.
- It is certainly impossible to erase all bad consequences of an
originally wrong choice of a category. E.g., if one wrongly
initialises/refines some ring R in the category of integral domains,
then one can construct the fraction field, and after
`R._unset_category()` the wrong fraction field would still exist, and
would still be accessible from `R`. Hence, unsetting the category may
help to cope with some mistakes, but it can of course not be a global
eraser.

URL: http://trac.sagemath.org/15234
Reported by: SimonKing
Ticket author(s): Simon King
Reviewer(s): Volker Braun
Trac #14814: Multivariate power series are missing integral and division method

{{{
sage: R.<x>=PowerSeriesRing(QQ, 'x')
sage: (x+x^2).integral()
1/2*x^2 + 1/3*x^3
sage: R.<x,y>=PowerSeriesRing(QQ, 'x y')
sage: (x+x^2).integral(x)
...
AttributeError: 'MPowerSeries' object has no attribute 'integral'
}}}

I also implement division by a non unit series (thanks Nicolas for
preliminary code) and fixes the latex method which was buggy

Apply:

* [attachment:trac_14814-power_series_inverse_latex-fix-fh.patch​]
* [attachment:trac_14814_review.patch​]
* [attachment:trac_14814-review-2-dg.patch]

URL: http://trac.sagemath.org/14814
Reported by: hivert
Ticket author(s): Florent Hivert, Nicolas Thiéry
Reviewer(s): Frédéric Chapoton