Reimplement `bin/mt-*` in terms of `make *`.
Simplify the mt-* interface.

If a developer wants to use mt-*, there are only three command
s/he has to deal with. Now `mt-make` is just a pass-through
interface for make. The advantage of mt-* is that once it is
in your path, you can run it from anywhere.

* `mt-setup` - Source this to add bin/ to your path and define PREFIX.
* `mt-configure` - Runs autogen.sh
* `mt-make` - Runs make passing through command-line arguments.

Here is a typical work-flow.

    $ cd mousetrap
    $ source bin/mt-setup
    $ mt-configure          # make the Makefile
    $ cd src/mousetrap
    $ vim something         # do some work
    $ mt-make check         # see if it passes unit-tests
    $ mt-make run           # try running it
    $ mt-make lint          # see how messy your code is
    $ mt-make clean         # clean up files generated by make
    $ git add ...
    $ git commit ...
    $ mt-make pristine      # clean up all files git is ignoring
                            # or not tracking
Delete obsolete mt-* commands.
Speed up and make mt-guess-prefix more accurate.
Add --dump-config and --config options.
Document built-in config file and add `--dump-annotated`.

We want to keep the documentation of the configuration file
as close to the source as possible. What better way than to
put the documentation in the configuration file itself?

To give the user convenient access to this annotated
configuration file. I add `--dump-annotated` command-line
option. This is needed since `--dump-config` dumps the
parsed and merged configurations on the search path, which
does not preserve comments.
`make clean` deletes `build/` generated by `make`.

`make clean` should delete anything that building created [1].

[1] https://www.gnu.org/prep/standards/html_node/Standard-Targets.html
Add `make devclean`. Fix comments. Adjust README.md.
Point `make clean` to $(builddir) whenever possible.
Remove local configurations.
Split out core.py from main.py.

main.py is now responsible only for bootstraping. This includes
parsing command line arguments, loading configuration, and
initializing logging.
MouseTrap, not mouseTrap