Add david-dm
update request and underscore
better checking of invalid zipfiles + adapt to no throw behavior of libzip 0.11.1 - refs https://github.com/springmeyer/node-zipfile/issues/33
start using node-zipfile 0.4.0 to support node v0.10.x
write empty file to simulate corrupt data rather than the string 'bogus data' which triggers a libzip segfault - refs https://github.com/springmeyer/node-zipfile/issues/33
bump to v0.6.0