Several speedups (use fromkeys to generate a new variables/constraints dictionary if n > 350 to remove).
Merge branch 'devel' into speedup
small fix
Container.__setitem__ has been modified to also allow for keys like Container['key'] = value

It doesn't allow the additions of new items though.
Merge branch 'devel' into speedup
Remove obsolete assertRaises test for container['key']
Merge pull request #3 from biosustain/speedup

Speedup