We keep stdout closed, which seems to have the side-effect of
stdout being connected to your TTY, in case you run a terminal.

However, this shold also prevent deadlocks, as only stderr is used.
The alternative would have been to try to fetch lines concurrently,
and we have been there.

For clone(), `communicate()` is used, and with some luck this will
just do the right thing. Even though last time I checked, it
didn't ... ? Lets see.

Stab at #72

Previously, it could have happened that pipes ran full, deadlocking the operation

Related to #72

signal.SIGKILL is not available on Windows so use signal.SIGTERM as a backup
when SIGKILL is not available.

For more information, see CHANGES.rst

Fixes #369

The problem is that a per-tree modification API cannot work properly, as the sorting is based
on full paths of all entries within the repository. This feat can only be achieved by the index,
which to my knowledge already does it correctly.

The only fix is to remove the misleading API entirely, which will happen in the next commit.

Related to #369

[skip ci]

Previously it was possible to generate trees which didn't
appear legit to git as gitpython's sorting was a simple alpha-numeric
sort. Git uses one that minimizes literal string comparisons though,
and thus behaves slightly differently sometimes.

Fixes #369