remove old external.js

this is unused and old, and we no longer ship custom minified-only js.
add keyboard shortcut to docs, closes #2960
Escape filename for pdflatex, otherwise filenames with spaces cause issues.
update CodeMirror component to 3.15
Merge pull request #3864 from ivanov/fix-2960

add keyboard shortcut to docs

closes #2960
Merge pull request #3861 from minrk/external-js

remove old external.js
Add new filter tests
Remove noise in test output
Fix fuzzy compare logic
Add leave_padding option to fuzzy compare
Added highlight tests
Fixed highlight test for latest pygments
Silence INFO logging in test output
Use built in test comparison
Fix assert_equal ref
Provide a list of the command and argument to subprocess for PDF post-processor, which is a better way to avoid issues if there are spaces in the filename.
Fixed double single apostrophe
Removed accidentally uploaded diff file
Instead of fuzzy compare, check for tokens in output
Don't check explicit output, instead see if output contains what we want