update readme with #egg
add test graffle file
move export commands to export.py
temp comment out export_preview
move quick look export methods to export.py
start of QL models
match embedded preview regardless of filetype
have quick look return previews of any filetype
add Pillow to reqs, importing version # from package is bad
remove png_path, use export() instead
simpler api
don't require pillow
add PyPDF2 as a requirement
stitch sketch pdfs together if multipage
add python-magic as a req
use mime type instead of relying on extension
update install instructions
add preview tests for sketch
graffle test
update readme