Update transform to use compileClient as the client opt is now deprecated

I began receiving the following when applying the transform with jade 1.0:

```
Error: The `client` option is deprecated, use `jade.compileClient`
    at Function.res.toString (/Users/will/src/ayr-frontend/node_modules/jade/lib/jade.js:164:17)
    at compile (/Users/will/src/ayr-frontend/node_modules/browserify-jade/index.js:96:24)
```

This uses the newer compileClient call but unfortunately isn't compatible with jade pre 1.0.