Btest

* btest-sphinx now provides a new directive btest-include. This
works like literalinclude (with all its options) but it also saves
a version of the included text as a test to detect changes. (Robin
Sommer)

* Fix typos and reST formatting in README (Daniel Thayer)

* Fix a couple of error messages. (Daniel Thayer)

* Fixed a reference to a non-existent variable which was causing the
"-w" option to have no effect. (Daniel Thayer)

* Test portability fix. (Robin Sommer)

* New "Sphinx-mode" for BTest, activated with -S. This allows to
capture a test's diagnostic output when running from inside
Sphinx; the output will now be inserted into the generated
document. (Robin Sommer)

* Adding an option -n to btest-rst-cmd that truncates output longer
than N lines. (Robin Sommer)

* Adding a PartFinalizer that runs a commmand at the completion of
each test part. (Robin Sommer)

* Improve cleanup of processes that don't terminate with
btest-bg-wait. (Jon Siwek)

* Fixing test portability problems. (Daniel Thayer)

* Adding TEST_BASE environment variable. The existing TESTBASE isn't
always behaving as expected and wasn't documented to begin with.
(Robin Sommer)

* Bugfix for ignored tests. (Robin Sommer)