Refactor to create PomBase::Chobo::{ChadoIO,FileIO,ChadoData,FileData}

[kimrutherford]

Restructuring:

• PomBase::Chobo::ChadoIO - read/write Chado
• PomBase::Chobo::ChadoData - an in memory representation of the Chado data that mirrors the table structure (more or less), including row ids (where known)
• PomBase::Chobo::FileIO - read/(write?) OBO files
• PomBase::Chobo::FileData - in memory rep. of data from an OBO file

Add methods:

• PomBase::Chobo::ChadoData::update($self, $file_data) {}
• PomBase::Chobo::ChadoIO::store($self, $chado_data)
• PomBase::Chobo::ChadoIO::read($self) -> returns $chado_data
• PomBase::Chobo::FIleIO::read($self) -> returns $file_data