Refactoring: Move options from cli.py to cli_opts.py

The cli.py module exceeded our max-module-lines limit and needs to be
split.

This pulls out all command line option definitions into a separate module.

It uses cli_opts instead of cli.opts since importing a module below
your own path causes problems if you want to re-export everything
from the lower module (which we want in this case).

Signed-off-by: Niklas Hambuechen <niklash@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>
qa: Default to tty=False for SSH

This fixes commands over SSH, such as `AssertCommand()`,
putting both stderr and stdout of the remote command into the
stdout of the SSH, which led to `AssertCommand()` seeing different
output than the invoked commands actually produce.

The `tty` option was originally added to *disable* `-t` (see commits
50265802 and f14a8b15), so we can as well make that the default.

Signed-off-by: Niklas Hambuechen <niklash@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>
pylintrc: Set `indent-after-paren`

This is to conform with our style guide.

This setting was added in and becomes necessary with pylint 1.3.

Signed-off-by: Niklas Hambuechen <niklash@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>
build_chroot: make group configurable and add documentation

This improves the 'build_chroot' script in two ways:
- It is now possible to configure the group of non-root
  users that can use the chroot.
- Some documentation about the configuration of various
  fstab files is added.

Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>