GlobalConfigurationFixture uses unit-tests.conf to determine default
and module specific logging levels. Logging will gracefully default to
INFO if unit-tests.conf is not found. See unit-tests.conf.sample for a
sample configuration file.
refs: #1375, #1267
Change-Id: Ib0c4eb4149748e6658f94ef1afa23ddd3072c0fa
rename configuration file's "keyfile" field to "certfile" to reflect usage of
an NDN certificate
nfd.conf certfile paths are now interpreted as relative to nfd.conf's location
refs: #1332
Change-Id: Ib91cffd3d113ef084bf19e87a85172ddfd16b7eb