Strontium

This release contains:

• small improvements and bug fixes,
• refactor of the astronomy.py module
• new test suite
• new documentation

Lithium

Several smaller bug fixes, including ppn.get decayed, and README.

Helium

• release for PyPI
• updated documentation
• update some defaults and some bug fixes

Hydrogen

This release has still functions and methods that have bugs, and some functions may behave differently then documented.