Integrate cobra and viper

Makefile

build/deps.sh

dfssc/authenticate.go

dfssc/cmd/authenticate.go

dfssc/cmd/fetch.go

dfssc/cmd/impexp.go

dfssc/cmd/new.go

dfssc/cmd/register.go

dfssc/cmd/root.go

dfssc/cmd/show.go

dfssc/cmd/sign.go

dfssc/cmd/version.go

dfssc/common/viper_helper.go

dfssc/fetch.go

dfssc/impexp.go

dfssc/main.go

dfssc/security/auth.go

dfssc/security/request.go

dfssc/security/security_test.go

dfssc/sign.go