Review of CombineFile Code

I am looking to experiment with combing files a bit, but first started doing some maintenance work:

• Use Java 8 facilities
• General clean up
• Remove use of checked IOException ("Signals that an I/O exception of some sort has occurred.") for validation errors
• Fix checkstyles

https://docs.oracle.com/javase/8/docs/api/index.html?java/io/IOException.html