changes made to tanks.py such that the local optimizer chooses fuel and radius for cylindrical cases, but only fuel for spherical cases.

old code in missions.py removed

execute sequence for 'gto payload release, nso tank release' expanded

additional set methods added to NTR() spacecraft Class and Mission() Class
had to resolve conflicts in tanks.py

Merge branch 'master' of https://github.com/Dreyrden/NTR14

Conflicts:
	src/tanks.py