Btest

* BTest is now hosted along with the other Bro repositories on
git.bro-ids.org.

* In btest.cfg, option values can now include commands to execute in
backticks.

Example:

[environment]
CC=clang -emit-llvm -g `hilti-config --cflags`

* Limiting substitutions to replacing whole words.

* Adding "substitutions". Substitutions are similar to filters, yet
they do not adapt the input but the command line being exectued.
See README for more information.

* Instead of giving a test's file name on the command line, one can
now also use its "dotted" name as it's printed out when btest is
running (e.g., "foo.bar"). That allows for easier copy/paste.

* Starting CHANGES.

* Fix the btest-rst-pipe script. (Daniel Thayer)

* A set of of documentation fixes, clarifications, and extensions.
(Daniel Thayer)

* A set of changes to Sphinx commands and directives. (Robin Sommer)

btest-rst-*:
- Always show line numbers.

- Highlight the command executed.

- rst-cmd-include gets an option -n <i> to include only upto i lines.

- rst-cmd-include prefixes output with "<file>" to show what we're
including.

btest-include:
- Set Pygments language automatically if we show a file with an
extension we know (in particular ".bro").

- Prefix output with "<file>" to show what we're including.

* Remove code to expand environment variables on command line. (Not
needed because the command line is just passed to the shell.)
(Daniel Thayer)

* Clarify explanation about expansion of environment variables.
(Daniel Thayer)

* Fix errors in README and btest help output; added documentation
for the -q option. (Daniel Thayer)

* Fixed a bug in btest where it was looking for "filters-" (instead
of "filter-") in the btest config file. (Daniel Thayer)

* More graceful error handling at startup if btest.cfg not found.
(Robin Sommer)

* Python 2.4 compat changes. (Jon Siwek)

* When in brief mode, btest-diff now shows full output if we don't
have a baseline yet. (Robin Sommer)

* Adding executable permission back to script. (Robin Sommer)

* Cleaning up distribution. (Robin Sommer)