API
===

* refactor Dataset to be more logical and to have official data setters/getters

GUI
===

* arbitrary math. operations on datasets (x and y -> calc. dy automatically)
* combination of two datasets by math. operation
* add'l parameters
* export plot as python script / ipython notebook (?)
* sqwtas

Bugs
====

* str() -> unicode()
* fix initial guess Y axis chaos
