Road Map

1. Eliminate Roo Dependency
2. Allow exporting to all supported formats via Parsers. Parsers will provide to_format(from_array) methods for each format they support.
3. Support Sheet Layouts, which will define desired data structures to parse from sheets, as well as sections of the sheet to parse from. For example, I could define a sheet layout with a header row, and a hash structure. Sheets::Base.to_array would then give me an array of hashes for each row under the matching header row, with the keys as the header values.