Updated requirements

Some out of necessity, others because we haven't tested old versions for a while.

small update

Fix missing Na (amusecode#930)

replace if..else with try..except in bridge.py (amusecode#903)

* replace if..else with try..except

* add AttributeError exception

* Update bridge.py

Revert "fix seba makefile to not rebuild if download is already there"

This reverts commit f8d3ff7.

Merge branch 'main' of github.com:amusecode/amuse

Remove DOWNLOAD_CODES from Vader makefile

also add empty packages keyowrd in setup of amuse package

Add amuse-mesa package

Merge pull request amusecode#831 from silviatoonen/master

adding SeBa methods for getting the fallback and time_step