Exception thrown when invalid arguments are specified

```
tailor --xcode
Missing argument for option: xcode
Exception in thread "main" java.lang.NullPointerException
    at com.sleekbyte.tailor.Tailor.handleCLIException(Tailor.java:73)
    at com.sleekbyte.tailor.Tailor.main(Tailor.java:350)
```
