Support unicode range

[xiejiangzhi]

for example:

/[\u4e00-\u9fa5]{2,4}/.random_example # => "廢仅弙" 

[coveralls]

Coverage remained the same at 100.0% when pulling d97ab9d on xiejiangzhi:master into 9022973 on tom-lord:master.

[coveralls]

Coverage remained the same at 100.0% when pulling d97ab9d on xiejiangzhi:master into 9022973 on tom-lord:master.

[coveralls]

Coverage remained the same at 100.0% when pulling d97ab9d on xiejiangzhi:master into 9022973 on tom-lord:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 98d562f on xiejiangzhi:master into 412920b on tom-lord:master.

[xiejiangzhi]

The CI is failed before my changes.

[tom-lord]

CI should be fixed now, sorry.
I think we should add spec/examples.txt to the .gitignore before merging; I'll look through these change more carefully later if CI goes green.

Thanks for the contribution 😃

[xiejiangzhi]

Hi @tom-lord , I removed spec/examples.txt.

[tom-lord]

👍 Thanks!