Add support for array of regexps in Client#whitelist

Also I fixed specs that suggested to pass `/example\.com/` to `#whitelist` which won't work as expected as the following code is executed at back end of Browsermob Proxy:
```java
for (Pattern pattern : whitelistEntry.patterns) {
  if (pattern.matcher(url).matches()) {
    found = true;
    break;
  }
}
```

[In Java `#matches()` matches the entire string, not just part](http://docs.oracle.com/javase/7/docs/api/java/util/regex/Matcher.html). As `/example\.com/` will not match `"http://www.example.com"` I think it's not a good example for specs.