Added dedicated HTML doc directory, so users can access HTML docs before compiling everything. Also added the beginnings of a comprehensive developers' README_dev, replaced the old README. Fixed OpenMP problems for SED mode. Added some brief documentation to plot_utilities.py and testing_against_mie_theory.py.
Added untracked files? I don't think there are any changes here...
Merge branch 'hoffman'
...I'm not sure why I'm being asked to explain myself. The merge should just add the changes that were in the hoffman branch on my local machine. Changes include fixing the OpenMP version of the SED mode, and adding some documentation.