v1.4.7

Small functionality additions:

• Pandas DataFrame conversion can be done without importing pandas, simply use the to_df() method, more on README
• Caching on results using lru_cache
• Password is an optional argument but will be prompted using getpass when not provided, this allows one to conceal their password all the time when using autokattis
• Remove nesting on ranklist JSON so the DataFrame version is more usable

Full Changelog: v1.4.6...v1.4.7