Debugged rectwires

answers are sensible though not tested
removed call to np.array for speedup

~2x improvement on atomchip_ideal
removed useless bfieldcalcs

~3x speedup!
cleaned up bfsimulator
refactored bfsimulator

farmed out field calculations to small functions, reduced code
duplication
added scipy trap finding

trying to use optimization to find trap center
huge speedup

switched to simplex trap finding and looser grid. Very quick now.
added numdifftools

now calculating trap frequencies using a library for numerical
calculation of hessians
preparing for testing
tests failing...