Gk browser find realm files

Displays all realms on the hard drive in a convenient menu

https://www.dropbox.com/s/tvbckphmqag28nk/Screenshot%202014-09-08%2016.35.13.png?dl=0

It would seems so, but it actually doesn't work. It causes an exception:
```
Unable to parse the format string "(kMDItemFSName like[c] *.realm)"
```

Probably because it's a "format", so it expects at least two parameters. And there is no equivalent predicateWithString method. I seem to remember I even lifted this line from an apple example, although I can be wrong about that.