fix cloze+latex issue in media check, and duplicate answers (#757, #758)

we were replacing spans with spaces during review but not during media check.
just strip the tags instead, which makes the media check consistent and
doesn't result in multiple identical answers
make sure to update order when adding/deleting/changing option groups (#675)
safe mode won't work on 4.7
add mature today stat
prioritize html over images to fix MS issue (#449)

this means that copying&pasting images on linux/firefox will redownload the
image which is wasteful, but Windows users make up the majority of the
userbase
ignore _ in field references (#803)
default to deckname.apkg on single deck export (#618)
Escape deck characters as necessary in suggested deck export path
need to strip trailing <br /> when saving fields
experimental type answer refactor

- when answer not correct, show both the given and correct string in separate
  markup. we use red/green for the given string to indicate what was correct,
  but we use grey rather than red on the correct string to indicate what was
  missing, as red is misleading
- colours can now be customized in css with .typeGood, .typeBad and
  .typeMissing
- answer now shown in monospace so given/correct lines up; can be customized
  with code#typeans
- do away with 'correct answer was' text that people didn't like
a hack to ensure hr falls before answer comparsion
add real example to card layout, and move hr like during review
turn off autojunking

seems to give better results on long passages, eg
https://anki.tenderapp.com/discussions/ankidesktop/1108-the-typing-diffs-are-sometimes-less-than-helpful
Add editFocusGained hook
Merge pull request #30 from hoelzro/master

Add editFocusGained hook
Merge pull request #29 from hans/patch/618

default to deckname.apkg on single deck export (#618)
more exporting fixes

- make sure we default to last saved export location
- make sure we filter out backslash
- use fname not initial_path, because we're not passing in a path
Merge remote-tracking branch 'dae/master' into flake

Conflicts:
	aqt/exporting.py
	aqt/reviewer.py
	aqt/utils.py
Re-flake
Fix an import typo