Bump version to 1.2.1

Bump version to 1.2.0

Full conversion to typescript (#5)

* Full conversion to typescript

* Fix export logic

* README fixes

* Version bump to 1.1.0

While this looks like a significant change, the code is semantically the same as before

getAddress is a typo and has been renamed to the correct getPublicKey. I'm the only user of this repo at this time and I'll be changing all references to the correct one when updating to this version so I consider this all a minor change.

Breaking change:
- getAddress is now getPublicKey (which is what it should've been in the first place)

Change version to 1.0.0

Merge pull request #4 from coderofstuff/path-for-change-2

Allow passing path type and index for change