Initial automated testing harness for flux-sched

Added initial support for a shareness-based automated testing harness. I added two test cases in the `t` directory and more test cases will be designed and populated in this directory. My plan is to ultimately use the same testing convention and methods as as flux-core (including auto tools and Travis CI support). For now, an easiest way to run these tests would be by *make check* at the root or `t` directory level. One should still be able to run each individual test script though. 

```sh
$ pwd
/g/g0/dahn/fluxdev_space/flux-sched
$ make
$ make check

ok 1 - success is reported like this
not ok 2 - pretend we have a known breakage # TODO known breakage
ok 3 - pretend we have a fully passing test suite
ok 4 - pretend we have a partially passing test suite
ok 5 - pretend we have a known breakage
ok 6 - pretend we have fixed a known breakage
ok 7 - pretend we have fixed one of two known breakages (run in sub sharness)
ok 8 - pretend we have a pass, fail, and known breakage
ok 9 - pretend we have a mix of all possible results
ok 10 - test runs if prerequisite is satisfied
ok 11 # skip unmet prerequisite causes test to be skipped (missing DONTHAVEIT)
ok 12 - test runs if prerequisites are satisfied
ok 13 # skip unmet prerequisites causes test to be skipped (missing DONTHAVEIT of HAVEIT,DONTHAVEIT)
ok 14 # skip unmet prerequisites causes test to be skipped (missing DONTHAVEIT of DONTHAVEIT,HAVEIT)
ok 15 - tests clean up after themselves
ok 16 - tests clean up even on failures
ok 17 - cleanup functions tun at the end of the test
# still have 1 known breakage(s)
# passed all remaining 16 test(s)
1..17

<CUT>
ok 1 - flux-module load works
ok 2 - flux-module list
# passed all 2 test(s)
1..2
```