Starting to set up P3M
Setting up long range solvers
Corrected constants
Model notes and testing new solver
Correcting constant parameters
Playing with different values of beta
Corrected bad conj call in solver.

Also added a cell that compare PM with P3M E fields calculated for two points.
Building and debugging short range interation calculations
Handle future warning.

x0==None will result in elementwise comparison in the future. Replaced with x0 is None
Basic short range calc function
First pass at p3m pp calcs
Sort particles by chain-mesh cell
Starting to update sr force calcuations.
Corrected long range mesh force calc.

Fixed issue with bad def of gaussian FT.
Added alias sum to build k2 for gaussian.
Correct handling of periodic perticle neighboors
Moved short range calc to c
Basic openmp
Calc short range adding directly into E at points arrays
Option to choose solver in landau
Updated dispersion plots and tests