add meta pow function for integer and half integer exponents
add integer and half-integer versions to inverse power cpp
add Hook (pow==2) wrapping, fix cpp bugs
add Hertz (pow==2.5) wrapping
pull sqrt out of bracket, add basic meta pow cpp tests
add more meta pow tests
put all power potentials into same python class
fix numerical issues in pow test
add cpp tests for integer and half integer templates in power potential
resolve conflict
add references
add static asserts for exponent values
Merge remote-tracking branch 'upstream/master' into power_pot_templates
updates to documentation
use SQL BETWEEN in Database addMinimum and addTransitionState

a single filter of between(emin, emax) should be faster than two
filters (e > emin) and (e < emax)
add some test for the spin potentials
remove a lot of the python neighbor list classes

They were not tested very well and they should ultimately be written
properly in c++.

I left the classes that were actively used by BLJ frozen potentials
add an explicit test for double ended commit
add some tests for linear algebra rates

also, comment out some unused functions
add an explicit test for NEB

also, fix a bug in NEB.  When niter is multiplied by factor we must
ensure it remains an integer self.factor