Adding all new code, removed a lot obsolete code and fixed import paths etc.

Mac OS X launcher:
* UI built on Swift
  * Why?
    * Apple seems to on purpose make it harder to get into Objective-C these days
    * Swift is compiled to native code, but has easiness of Javascript in programming
    * Perfect for the OS X UI, many guides & tutorials as well
* "Backend" in Objective-C++ / C++14
  * Why?
    * Originally written in Objective-C / C++14 with C++17 backports
    * Only for backend because of the time the development takes
    *

Short summary of features:

* Java
  * It can detect java from:
    * JAVA_HOME environment variable
    * "Internet Plug-Ins" Apple stuff
    * By the /usr/libexec/java_home binary helper
  * It can unpack a new version of I2P
    * Unpacks to ~/Library/I2P
    * Can check currently unpacked version in ~/Library/I2P via i2p.jar's "net.i2p.CoreVersion"

  * User Interface (a popover, see https://youtu.be/k8L3lQ5rUq0 for example of this concept)
    * Router control tab view
      * It can start the router
      * It can stop the router
      * It can detect already running router, then avoid fireing up one
      * It can show basic information about the router state & version
    * Log view tab (not yet done)
  * While left-click triggers popover, right-click draws a minimal context menu