Release 1.6.0

Add calculate_absorption_background(), which is needed for self-absorption correction by external applications

Release 1.5.1

minor updates (update placeholder texts)

Release 1.5.0

Add two lists of predefined materials -- compounds and elemental.

Release 1.4.5

Improved About dialog
Edited calculation formulas and docstrings

Release 1.4.4

bug fix release

Release 1.4.3

bug fix release

Release 1.4.2

bug fix release

Release 1.4.1

bug fix release

Release 1.4.0

add gas mixer

Release 1.3.9

with updated setup.py that puts XAFSmassCalc.py start script to the standard Scripts directory.