Add tests for boxy types

-farity -ddump-idinfo is added for the compilation and the dumpped output is supposed to match .stderr

Revamp the testsuite framework.  The previous framework was an
experiment that got a little out of control - a whole new language
with an interpreter written in Haskell was rather heavyweight and left
us with a maintenance problem.

So the new test driver is written in Python.  The downside is that you
need Python to run the testsuite, but we don't think that's too big a
problem since it only affects developers and Python installs pretty
easily onto everything these days.

Highlights:

  - 790 lines of Python, vs. 5300 lines of Haskell + 720 lines of
    <strange made-up language>.

  - the framework supports running tests in various "ways", which should
    catch more bugs.  By default, each test is run in three ways:
    normal, -O, and -O -fasm.  Additionally, if profiling libraries
    have been built, another way (-O -prof -auto-all) is added.  I plan
    to also add a 'GHCi' way.

    Running tests multiple ways has already shown up some new bugs!

  - documentation is in the README file and is somewhat improved.

  - the framework is rather less GHC-specific, and could without much
    difficulty be coaxed into using other compilers.  Most of the
    GHC-specificness is in a separate configuration file (config/ghc).

Things may need a while to settle down.  Expect some unexpected
failures.

Add Makefile

Add a Makefile here.

Use makefiles in the subdirectories to ease running the test driver in
a subdirectory.  It can be run in the following ways:

 	make		-- run all the tests in the current directory
 	make verbose	-- as make test, but up the verbosity
 	make accept	-- run the tests, accepting the current output

and you can also set some variables on the command line, eg.

	make accept TESTS=arr001  -- accept an individual test
	make EXTRA_HC_OPTS='-v'   -- extra flags to the haskell compiler
	make CONFIG=<config>	  -- use a different test config

this will all go in the docs at some point.