Also tweak colored output to reset before the newline instead of after,
so travis behaves better (for some reason reset causes travis to display
the line in black).
Split test_interactive off from test_fishscript and add a new target
test_high_level that tests both.
Add some Makefile magic so the tests can be run serially without using
sub-make, which gets rid of a little noise from the make output.
Rewrite interactive tests to look better.
As far as I know we can't access the build artifacts from Travis, so we
can't check the interactive logs after a test failure. Add an
environment variable that causes the test runner to dump the logs
itself, and set that variable for Travis.
