[BUG] Fix Amount.to_human_full()
* Amount.is_native is a function, but was referenced as a bool.
* Duplicate to_text_full tests to test to_human_full.
Merge pull request #167 from ximinez/ripd-549

[BUG] Fix Amount.to_human_full()
[DOC] update release notes
[TASK] bump version to 0.8.1-rc3
[TASK] bump version to 0.8.1