Merge branch 'master' into kai-branch
Merge branch 'master' into kai-branch
modification: ratio constraint

in add_ratio_constraint()
store m_id inside the model object instead of returning it
this allow the information to be pickled

added remove_ratio_costraint() function
bug fix:
add_ratio_constraint()
remove_ratio_constraint()
Revert 8ef181e..8a68186

This rolls back to commit 8ef181e17b6db979f6afc644f31594df0af84cee.
created the "hack" package.

added ratio_constraint.py to hack package.

implemented:
add_ratio_constraint()
remove_ratio_constraint()
list_pseudo_metabolites()
bug fix: remove_ratio_constraint()
Merge branch 'master' into kai-branch
added flux_envelope_3d()
- calculate the flux envelope for a triplet of reactions
Merge branch 'kai-branch'