v0.5.6

What's Changed

• Add real unit tests by @palewire in #377
• Replace all return None on errors with raised exceptions by @palewire in #378
• Add copy_chart method by @palewire in #379
• Add folder methods by @palewire in #381
• Add fork_chart method by @palewire in #380
• Patch fix tests by @chekos in #382

Full Changelog: v0.5.5...v0.5.6