Better RegEx support for "Formatting Strings" feature

This RegEx is used to transform variable names

```
/(^[A-Z]|)(?: ?(?:([A-Z])|(?: ([a-z])))([a-zA-Z]*))/gm
```

I am unable to say something like 
\u$1$2$3\l$4\e

The $ symbol doesn't work like it should in a RegEx substitution 
 