Crystallising the API (v0.4.0)

Crystallising the API

• Rename transfer methods. by @JoeZiminski in #360
• Rename get_next_sub_number and get_next_ses_number. by @JoeZiminski in #359
• Remove transfer options from make config file by @JoeZiminski in #361
• Remove central local path exist requirement by @JoeZiminski in #365

A new 'overwrite existing files' option

• Extend overwrite option by @JoeZiminski in #362

Reworking the documentation

• Update README.md for v0.3.0 by @JoeZiminski in #357
• Rework of docs before v0.4.0 by @JoeZiminski in #367

Full Changelog: v0.3.0...0.4.0