Add scons targets for running individual tests
Add scons targets for running individual tests

Now that there are several test cases, turning on debug mode can
clutter up the display.  This patch adds targets that let you run an
individual test program, rather than the whole test suite.  So, for a
test case defined in tests/test-foo.c, you can run “scons test-foo” to
run just that test case, or “scons test” to run them all.

dcreager/libpush,dcreager/libpush,dcreager/libpush