typo corrections in UVES tutorial
fix futher typos and update ApJ reference
add index html template
change path to template
add astropy word png
copy images into tmp
fix link to word image
capital D
catch failed git command
exit
fix links
added descriptive text
added nbconvert template
Remove 'tutorial' from heading
Removed tutorial from heading
force
First pass at tutorials

EJT: As originally written, this commit had large FITS files.  It has since
been modified to use `download_file`, and the fits files were removed from the
git commits to prevent requiring large downloads for those cloning the git repo.
But bear in mind that means all the commits from this one until `download_file`
was added won't work.
Finished a basic tutorial for fits images

Load the data, show it in linear and log scale, image stacking, and
writing fits files.
Finished a fits tutorial for fits tables

Also covers plotting 2d histograms
Cleaned up variable names and syntax

fits -> FITS
TEST_DATA -> image_data and event_file
some spaces removed