commit all of Marshall's current code minor mods
Merge pull request #4 from swolff9/swolffbranch

Added image and SED chisqrd calculators and the likelihood estimation fu...
resolve conflict with Schuyler's edits
resolve conflict with Schuyler's edits
Getting Schuyler's latest ipynb
Merge branch 'swolffbranch' of https://github.com/swolff9/mcfost-python
make .wavelengths a property rather than a constant for param files, so it updates if you change lambda_min or _max.
fix minor syntax errors
Add code to automatically clean up/delete any previous MCFOST output results when you run a new calculation that would write to the same output directory.
Improve object interface to images and SEDs.
Update and improve the notebook examples, for consistency with the current version of the package.
Updated the chisqr to allow for both integer and sub pixel shifts when calculating the image chisqrd. Also fixed bugs in the ccm_extinction utils.py function.
Merge branch 'master' of https://github.com/mperrin/mcfost-python into swolffbranch

Conflicts:
	mcfost/chisqr.py
	mcfost/utils.py
Merged issues between swolff and mperrin versions in utils.py. The codes were doing identical things.