util.c: clean up check_dnssl_presence and check_rdnss_presence
gram.y: This looks like a bug, but not sure...

I ran into some crashes while writing unit tests and found these
lines here.  I *think* the two lines under the else need to be
wrapped in curly braces.
gram.y: fix memory problems exposed by unit tests

Interfaces were not properly freed when the config file fails to parse.
scanner.l: AdvLifeTIme -> AdvLifeTime (I -> i)

This slipped past code review a while back, but was caught when writing
unit tests.
add print_safe_buffer
configure.ac: add PKG_CHECK_MODULES([CHECK])
add unit tests
add dnssl and rdnss checks
add test_add_ra_header
add test_prefix
send.c: add more unit tests
send.c: use a fixture in unit tests

Avoid reading and rereading the test config file over and over...
send.c: add lowpanco unit test

This exposed a bug in scanner.l where an 'I' meant to be an 'i'.
util.c: add test fixture for a couple unit tests

avoid reading and rereading the test config file.
Merge branch 'check_framework'