Add userphrase_ in UserphraseImporter
Parse userphrase json in constructor
Add isSupportedFormat() getUserphraseSet()
Use {} for constructor
Change UserphraseSet iterator to const_iterator
Add createUserphraseImporter
Don't use UserphraseImporter.load()
Use createUserphraseImporter()
Add newline at the end of file
Use const_iterator as const iterator
Add non-const begin() and end()
Add const to empty()
Remove load() in UserphraseSet