add License.md file
updated impro HTML documentation
Merge branch 'master' of https://github.com/moustakas/impro

Pulled License.md file from github.com
isedfit tweaks
added a photoz module to isedfit
updated charlot & fall dust model to pacifici+12
minor isedfit tweaks
removed extra line for SIII case
Update atomic data.  Still reviewing collision strengths.
added header update function
cleaned up extra comments
minor tweaks to isedfit_kcorrect
minor isedfit tweaks
deep2 filterlist and maggies changes; unwise_to_maggies written
minor tweaks to isedfit; added decam filters
isedfit photoz developments
fixed a small bug with how EWs were being calculated in isedfit_montegrids
isedfit_kcorrect now returns UV flux
isedfit: nebular spectrum now also written out
small tweak to isedfit_qaplot_sed