Introduce code coverage testing for libnaemon

It's the foundation upon which we put all other building blocks, so
let's be anal when we test it and aim for close to 100% code coverage,
minus the _strerror() functions and a few others that simply don't
apply.

Signed-off-by: Andreas Ericsson <ae@op5.se>
Show some love to the .gitignore files

Namely, ignore pretty much all test*.trs and test*.log files, although
we do so on a directory basis, since we may want to incorporate test
data later and that test-data will almost certainly have .log files if
we do.

Also, remove the tests from the t-tap directory .gitignore that haven't
been built these past five years.

Signed-off-by: Andreas Ericsson <ae@op5.se>