Merge pull request #11 from Michagogo/master

michagogo's gitian sigs for 0.8.4
wtogami's gitian sigs for 0.8.4
Merge pull request #12 from wtogami/master

wtogami's gitian sigs for 0.8.4
Gavin 0.8.4 sigs
laanwj 0.8.4 sigs