Include regex for Ve::PartOfSpeech.name to separate words with space

For example

    Ve::PartOfSpeech::ProperNoun.name => "proper noun"

With the current implementation the following yields

    Ve::PartOfSpeech::ProperNoun.name => "propernoun"

I tried looking at Ruby documentation for humanizing strings with uppercase, but didn't find any. Therefore, the use of ugly regex.