dfba & bioreactor

1. added id variables to both Organism and Bioreactor
2. changed the output of dFBA to t, V, X, S instead of t, y
Revert "removed flux_cone_projection()"

This reverts commit 534949a081e1c0f301054e7b2091cc7cced3abf8.
dFBA methods now returns a OrderedDict

dFBA methods now returns a OrderedDict containing simulation results
changed  the interface of Bioreactor __init__()

now allows organisms and metabolites to be set after the initial
construction of Bioreactor.