Merge pull request #2 from neg/master

init: do not need default value for opt -d
Change line break matching in execute

Match line breaks at end rather then at beginning to avoid out of sync
issues for some sources.
Fix incorrect (old) usage of fatal in unit tests

These should have been updated in fb0b28c
tap: do not call output before int::output_tap is set

A call into output before int::output_tap is set will result in a
stacktrace since output depends on int::output_tap to decide output
format.

Signed-off-by: Niklas Söderlund <niso@kth.se>