parse.go: Rename tokenZero to zed
parse.go: Rename tokenPeekCount to peekCount
go fmt fixes
Rename tests to REGEXable names
parse.go: Remove old error reporting methods
Remove Tree.stopParse()
Remove Tree.backup()
Remove dead code

Using go test -coverprofile showed a bunch of code that had become stale. Since
it was not needed for the current passing tests, it has been removed.
gitignore c.out