Changes in version 0.99.0 (2019-06-02)
+ Initial submission

Changes in version 1.1
+ Only convert 0's to NA's if there are no NA's in the dataset (commit 06df44a, fix issue #3)

Changes in version 1.3
+ Escape result coefficient names if result_names() is called and they contain potentially 
problematic characters (see issue #4)
