revisit use of tempfiles in cirq python interface

[alexandrupaler]

besides complicating the code, could tempfiles be useful for debugging strange simulations?

[s-mandra]

I don't think so: qFlex at the moment read once (and only once) the stream, so I don't know how tempfiles could help debugging. Removing the tempfiles is something I can do.

[alexandrupaler]

the tmp files work like logs of the interface between python and qflex. crashes may be in qflex, but the inputs are very large, so it makes sense to keep the tmp file mechanism. maybe it can be a switch at compilation.

[s-mandra]

Sounds good to me.