Remove unused files
Fix crash when no phoneme is found
Refactor: change unittest framework from cppunit to boost::unittest
Fix unit-test runtime failure in windows
Add function, Path::getExtension
Add class 'Oto'
Refactor 'UtauDB' class; use pimpl
Remove unused member functions in 'UtauDB' class
Modify 'Oto' class; add index accessing APIs
Refactor 'UtauDB' class; use 'Oto' class to manage oto.ini contents
Refactor 'UtauDB' class; use const reference if suitable
Add 'PrefixMap' class
Add 'note_number' argument to UtauDB::getParams
Refactor 'Sequence' class; use const reference for string arguments
Modify 'UtauDB' class; read prefix.map file in ctor
Read oto.ini files in sub directory
Fix runtime error in PrefixMap::Impl::getNoteNumber
Merge branch 'feature/support_prefixmap' into develop