Issue Description:

Based on RFC 1034:

> The labels must follow the rules for ARPANET host names. They must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen. There are also some restrictions on the length. Labels must be 63 characters or less.

but `spm_mangledToBundleIdentifier` doesn't fix hyphens at the end of labels or labels that are more than 63 characters long.