Refactoring and MIME Type for executable files

[lukaszimmermann]

• Updates the JDK version to 1.8
• Changes the Signature of the MIMETypeHelper functions to return Optional<String> rather than nullable String
• Some code formatting (no more whitespace in empty lines, no trailing whitespace)
• Remove unused imports
• Adds the GenericNodeView<T> class which allows to set the Component of the NodeView as a Lambda. Usage is demonstrated in the MimeFileImporterNodeFactory class.
• Adds the ZipUtils class to extract the implementation of reading and writing data from and to ZIP files from the Node Models.
• Various final modifiers added.
• Replace manual closing of resources with try-with-resources at some points.
• Executable, regular files (so especially no directories) are now associated with the exe extension automatically. This addresses #146
• Dialog of Input File now shows a JLabel with a live preview of the MIME Type of the selected file.

I can also chop this down into multiple PRs if necessary.

Example of the Preview:

[jpfeuffer]

Very cool. I'll have a close look today.

[rrahn]

Some how this broke the registerFile for the SeqAn Apps.

[rrahn]

Ok sorry, I might be not related at all. I will investigate this, but it seems, that someone did not update the mime types when updating the last yara release