Improve data errors output

[eelcoj]

Recently worked on a site that heavily uses Perron's programmatic content feature. Pretty cool, unless you have errors in your data files. Commas within your CSV values (and they are not wrapped in quotes) 😱

This should improve those errors. Example:

rails perron:sync_sources
bin/rails aborted!
Perron::Errors::DataParseError: Column mismatch in `~/site/app/content/data/platforms.csv` at row 8 (). Expected: id, name, description, contact_file_path, post_layout_path, default_layout_path, common_use_cases (Perron::Errors::DataParseError)