Fixed WindowsReporters to use cmd /c otherwise they didn't work properly
on windows(they were spawned on the background)
Changed a lot of stuff and fixed some bugs:

* Windows reporters should work properly now. Use the cmd /c hack to make the executable run on the foreground
* Add a new blank line on each approval file because some editors try to be clever - vim for sure
* Don't return a boolean from the approveNew but just return void. The user is responsible for moving the whole content from left to right
* Some approveNew commands can't use the file for verification because it doesn't yet exist. Provide a way for the user to change that in ExecutableDifferenceReporter
* Implemented SwingInteractiveReporter which was needed because of the above changes and I wanted to test the interface