attempt to fix differences in log instance only on CI
Merge branch 'develop' into fixci
change npm-test (fixes #7) & npm-cover

tap tests/*.js runs same tests (over-reporting number of tests),
but in separate processes, so istanbul can't provide coordinated
coverage. tap does exit with non-zero code if there are failures,
which is needed for travis.
Merge pull request #8 from isao/fixci

1. fixes a timing issue with requiring a module, exporting it,
   and using it from tests that are run in parallel..
2. proper exit code on travis