Update README.md
add a simple implementation of textrank
Merge pull request #190 from sing1ee/master

add a simple implementation of textrank
add some introduction of textrank
Merge pull request #191 from sing1ee/master

add some introduction of textrank
add custom dictionary to __main__; update README; slightly optimize textrank
improve README
fix English part of README
Merge pull request #192 from gumblex/master

更新、完善说明；命令行加入自定义词典功能
Merge pull request #1 from fxsjy/master

update