Classes for Hilbert modular groups

[fredstro]

Adding classes for Hilbert modular groups. Including congruence subgroups of SL(2,O) and conjugates of the type SL(2,O+a)
where O is a maximal order in a number field.

CC: @mstreng @sagetrac-florian

Component: number theory

Keywords: hilbert modular sd51

Work Issues: documentation, pyflakes warnings

Author: Fredrik Stromberg

Branch/Commit: public/ticket/14977 @ 629805f

Issue created by migration from https://trac.sagemath.org/ticket/14977

[fredstro]

Branch: u/fstromberg/ticket/14977

[mstreng]

Author: Fredrik Stromberg

[fchapoton]

comment:4

I have made a little clean-up of the code.

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New commits:

c1b1934	created a new ticket
fd728f8	added import of QQ
9e473a2	trac #14977 first clean up

[fchapoton]

Changed branch from u/fstromberg/ticket/14977 to u/chapoton/14977

[fchapoton]

Commit: 9e473a2

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

53d08af

trac #14977 make sure that tests pass

[sagetrac-git]

Changed commit from 9e473a2 to 53d08af

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

8afbbdb

trac #14977 more cleanup work done