Changes to mainWFG, added Kolmogorov & vonKarman

The WFG-for-main was giving unexplainable conflicts with the master. Now
created a new branch from the master and added the files to the new
branch and all seems to work just fine now.
Files should now work correctly, independent on OS, or start path.
Fixed file import in testNollMapping().
Fixed assertion problems.
Kolmogorov/von Karman aberrations

-Major update to von Karman/Kolmogorov aberrations: Now includes high
frequency content.
-Fixed a error: A multiplication in the PSD sould have been a addition
-Fixed a error: The grid creation: a minus sign added for the lower
limit

Joao, would you please check if you can agree on the results produced by
the code? I find phases in the range +/-20rad with spikes up to
+/-40rad, but then literature seems to give similar ranges. This might
also give problems in WFR, can their code/approximations handle such
large ranges? We'll see I suppose...
Choose aperture in zernike wavefront

Upon special request of some people: the circular aperture is not
applied automatically now in createWavetront(...), it however still is
present in plotWavefront(...) as a square grid it is mathematically
incorrect. If desired, it can still the applied and removed via the
'circAperture' flag in both function.
Solved issues in test file

On request I removed the circular apperture, but retained the old data
set with aperture. Should be fixed now.
Merge pull request #77 from faitdivers/WFGbranch

Changes to mainWFG, added Kolmogorov & vonKarman
Merge branch 'master' of https://github.com/faitdivers/pyao into WFRSouthwell
resolving conflicts