moved muskellib to items

formatter/formatter.go

items/command_call.go

items/helpers.go

items/helpers_test.go

items/items.go

items/parse_fragment_test.go

items/scale.go

items/scale_test.go

parser/body.go

parser/header.go

parser/helpers.go

parser/itemparser_test.go

parser/items.go

parser/note_test.go

score/bars.go

smf/instwriter.go

template/call.go

unroller/unroller.go