add EQ unit test "unit/fi_eq_test"

start of test for #48
currently uses fi_eq_write() to generate events, but need to use alternate mechanism for providers that do not support it.

tests still needed:
- EQ groups
- FI_WAIT_UNSPEC
- FI_WAIT_MUTEX
- readerr testing
- multi-threaded stress

question:  should the output be more granular about what all is being tested, or ok to refer to source to make sure provider is comfortable with coverage?

Signed-off-by: Reese Faucette <rfaucett@cisco.com>
ok, will look in common code and use something from there if appropriate or move this to common