Add series

Merge pull request #18 from Zsailer/clean-api

clean api

Add tree module.

Merge pull request #13 from Zsailer/tree

Add tree module

reorganized methods into `phylo` accessor

Previously, PhyloPandas attached methods directly to the Pandas DataFrame. This can cause confusion because it adds specific methods to the Pandas namespace.

This version, instead, adds a phylo accessor to the DataFrame that includes the extra write methods.

Core DataFrame now supersedes pandas.DataFrame

Merge pull request #9 from Zsailer/dataframe-core

revamp core dataframe

Fix alphabet bug in some formats.

Merge pull request #3 from Zsailer/alphabet-arg

add alphabet argument to read and write

small bug fixes

v0.1.2

bump version

First working release

v0.1.1

update version