schema-salad-tool --print-doc / schema-salad-doc: privacy leak

[mr-c]

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1003977

Regardless of command line options, an external resource (picturefil js) is always referenced.

Additionally, not providing --brandstyle leads to an external resource (bootstrap js) being used:

schema_salad/schema_salad/makedoc.py

Line 522 in 661fb0f

"https://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css"

We should include local copies and add an option to use these local copies.