Tweaks

[ffreyer]

Changes:

• cleanup and include measurement extensions (e.g. Fourier transform)
• added haskey(::MonteCarloFlavor, ::Symbol)
• added test for EachLocalQuadBySyncedDistance and test for directional sorting method
• changed ED checks to be per element, rather than matrix/vector norm (or whatever base does)
• changed ED to work with any lattice
• fixed thermalization measurements for DQMC (weren't changed to new system)
• added numerically exact ED check for Greens functions (equal and time displaced, at U = 0, beta =1, 10)
• added analytic check for noninteracting Greens functions
• added Sum wrapper for lattice iterators
• added noninteracting, interacting and total energy measurements + ED tests

I should probably clean this up and merge...

[ffreyer]

closes #18 ... probably

[ffreyer]

I'll wait with merging a bit to see if I run into any issues with the Sum wrapper

[ffreyer]

The Sum wrappers seems to be fine. Saves, loads and runs without issues.