csvp (aka csv+)

An "enhanced" CSV parser for use internally by csv++. The reasons we need a custom CSV parser and the csv crate will no longer suffice:

• Support for wrapping a cell across multiple lines.
• Comments (a row starting with #).
• Contextual information with each cell - in addition to just the value it parses to we need to know enough info about what line certain values happened on, in order to show proper highlighting and error messaging.