Improved output format and bug fixes

• Output now doesn't repeat the parameters section if several calculations are made. Therefore the input section has been separated from parameters.
  • To make this possible the function freesasa_log() has been deprecated and replaced by freesasa_write_parameters() and freesasa_write_result().
• A bug where unrecognized long-options caused seg-faults has been fixed.
• Errors from fprintf() are now caught more consistently throughout the library.
• CLI documentation has been expanded with a more elaborate example.