Backslash not working

[KarimGeiger]

Hi,

I was just updating the test rules in PR #13 and it seems like the backslash rule fails:

https://travis-ci.org/SimpleRegex/SRL-JavaScript/builds/264277712?utm_source=github_status&utm_medium=notification

[corsonknowles]

Thanks, I just pushed a commit that will double escape backslash, which should restore it to working order