Better Errors

[FourierTransformer]

Changes

• Changed how errors display, now include line number and ensure all toml.io links work
• Updated all errors that could occur during parser
• Removed _nsmerror in utf-8 validation and replaced with standard error handling
• In UTF-8 escaping, show the actual hex escape in the error message to make things easier
• Encoder shows which key failed and displays datetime errors nicely
• Added filesize and nesting depth options.

closes #11