update diffview to latest
Merge pull request #41 from victorhsieh/master

update diffview to latest
make corner and background color consistency
use 宋體-繁, change background-color, em use dot
correct Songti TC for 宋體-繁
update doc and remove deprecated info
split debates controller
Swithch diff library to diff-match-patch

Fixes #37
regen for 53e958b