Merge pull request #13 from cielavenir/master

export pem in pkcs8 to relax Chrome WebStore
Merge pull request #14 from cielavenir/master

show warning only if verbose is set; no ways to suppress it on JRuby
Merge pull request #15 from cielavenir/master

avoid creating temporary zip
Merge pull request #1 from Constellation/master

Merging latest crxmake into ciel's