Reintroduce 2c7bebb5f2c873850c2b2d82013cab4eb3d4913c
Merge branch 'blur-on-escape2' of https://github.com/mrmr1993/vimium into mrmr1993-blur-on-escape2
Add comment regarding .blur() on embeds.

Including embeds for .blur() etc. here is experimental.  It appears to
be the right thing to do for most common use cases.  However, it could
also cripple flash-based sites and games.  See discussion in #1211
and #1194.