Switch to scl, an extension of hcl

cmd/cashierd/main.go

server/config/config.go

server/config/config_test.go

server/config/testdata/config.go

server/config/testdata/empty.config

server/config/testdata/test.config

vendor/github.com/hashicorp/hcl/hcl/parser/parser.go

vendor/github.com/homemade/scl/LICENSE

vendor/github.com/homemade/scl/decode.go

vendor/github.com/homemade/scl/disk_file_system.go

vendor/github.com/homemade/scl/doc.go

vendor/github.com/homemade/scl/file_system.go

vendor/github.com/homemade/scl/glide.lock

vendor/github.com/homemade/scl/glide.yaml

vendor/github.com/homemade/scl/parser.go

vendor/github.com/homemade/scl/readme.markdown

vendor/github.com/homemade/scl/scanner.go

vendor/github.com/homemade/scl/scanner_line.go

vendor/github.com/homemade/scl/scope.go

vendor/github.com/homemade/scl/token.go