`rst-shift-region` now works like `indent-rigidly`. I.e. you can give

`rst-shift-region` now works like `indent-rigidly`. I.e. you can give
a positive or negative argument to control direction and amount of
reStructuredText indendation points you want to change indendation by.
There is only one key binding on C-c C-r TAB.

`rst-shift-region` does not fill any more - this should be left to the
user. Variable `rst-shift-fill-region` is removed therefore.

Debugging: `rst-compute-tabs` operates more consistently.
`rst-shift-region` doesn't drop the region.

`rst-indent-width` has been renamed from `rst-shift-basic-offset` and
is customizable.

`rst-preferred-adornments` has a proper customization type.

General refactorings.

Revised and added ideas.

Added and improved lots of tests.

git-svn-id: https://docutils.svn.sourceforge.net/svnroot/docutils/trunk@6713 929543f6-e4f2-0310-98a6-ba3bd3dd1d04