Improve count_points

I use Harvey's algorithm already in sage to speed up the computations.
Refactor point counting code for hyperelliptic curves.
First bunch of fixes and missing examples.
Rebase on top of #15108.
Merge remote-tracking branch 'trac/develop' into ticket/15148

Conflicts:
	src/sage/schemes/hyperelliptic_curves/hyperelliptic_finite_field.py
Trac #13942: Correct some wrong statements on the Magma interface in Sage

The following statements in the explanation of the Magma interface in
Sage are wrong, and may misguide a user.

magma(expr) - Evaluation of arbitrary Magma expressions, with the result
returned as a string.
magma.new(expr) - Creation of a Sage object that wraps a Magma object.

URL: http://trac.sagemath.org/13942
Reported by: klee
Ticket author(s): Kwankyu Lee
Reviewer(s): Volker Braun
Trac #14695: Don't (re)run ranlib in sage-location

Doing so is useless and only wastes (potentially a lot of) time.

----

'''Apply:''' [attachment:trac_14695-dont_rerun_ranlib.scripts.patch] to
the '''scripts''' repository.

URL: http://trac.sagemath.org/14695
Reported by: leif
Ticket author(s): Leif Leonhardy
Reviewer(s): Volker Braun
Trac #15148: Improve point counting for hyperelliptic curves

Harvey's hypellfrob program is shipped with Sage but was not actually
used to count points on hyperelliptic curves.

This ticket intends to fix that (and add several other minor
improvements).

URL: http://trac.sagemath.org/15148
Reported by: goncalves
Ticket author(s): Cécile Gonçalves, Jean-Pierre Flori, Jan Tuitman
Reviewer(s): Jan Tuitman, Jennifer Balakrishnan, Volker Braun