escape modloadmsg

when you use something like this in a easyconfig, you need to scape $

```
modloadmsg = """To list all the available utilities execute ls \\$EBROOTPICARD"""
```

With this fix easybuild will take care of scaping 

`$` has to be escaped for both Tcl and Lua module files, so doesn't have to be moved into the class imho.