Propagation of FWAction's only happens for last Firetask in Firework

[utf]

The FWAction.propagate option (see #407) only takes effect if the FWAction is from the last Firetask in the Firework, otherwise it is ignored, due to the way FWActions are amalgamated.

E.g. the code surrounding:

fireworks/fireworks/core/rocket.py

Line 322 in 32b1ea9

all_mod_spec.extend(m_action.mod_spec)

One fix would be to make the amalgamated FWAction propagate if ANY of the previous FWAction's had propagate=True. Other than that, I don't see an easy fix without completely rewriting the way FWActions are applied.

Tagging @jotelha in case they have any ideas.