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.
Small fixes. Model reduction approach removed (to be included in experimental branch).
Merge branch 'master' of https://github.com/cdanielmachado/framed

Conflicts:
	src/framed/analysis/variability.py
Re-ran tests after merge. All ok.
catching up to Master
resolved conflicts