testsuite: add automake's tap-driver.sh

Add config/tap-driver.sh from automake 1.14.1 so we aren't required
to AC_REQUIRE_AUX_FILE() on it (since using this macro when it's
argument doesn't exist seems to break older automakes)
testsuite: use automake's TAP driver for TAP tests

Use automake's tap-driver.sh to drive TAP tests, which results
in an accurate summary of all TAP test output (though overall test
output is more verbose). This will have no effect on older automake
versions that do not support parallel-tests.
testsuite: modify spellcheck to issue TAP output

Make the spellcheck test output results in TAP to mirror other tests.
fix EXTRA_DIST in src/bindings/lua/Makefile.am

EXTRA_DIST was erroneously referring to old unit test drivers,
and should instead be referring to lua-TestMore held under
the 'Test' directory.
testsuite: add .travis.yml

Add travis-ci.org integration with .travis.yml file in top-level
of repository.
testsuite: spellcheck: skip tests if no aspell is found

Skip all tests if no aspell program is found.
testsuite: Install aspell in travis-ci image
Merge pull request #46 from grondo/testsuite-updates-for-travis-ci

Testsuite updates including integration with travis-ci.org