Can we omit freezing/unfreezing the BPO parameters?

[anilbey]

EModelRunner uses BluePyOpt to apply the protocols to the cell, not to optimise the cell model. There is some hacky freeze/unfreeze frozen/unfrozen parameter specification logic happening in EModelRunner however. Can that be omitted or can the freezing of the parameters performed only once with the cell creation? That would simplify the logic and save the computer from unnecessary operations.

[anilbey]

#89 was a failed attempt to remove the freezing operations.