Magic iPerf including iPerf3 APK

Magic iPerf is tool that actively measures achievable data rate on IP networks. This tool is designed for experienced users of iPerf or iPerf3 and requires at least two devices for network performance measurement. Besides your phone/tablet running this App, you will need another phone/tablet running this App or another PC running the conventional iPerf/iPerf3.

The two main features I've added are:
1. Support of both iPerf and iPerf3
2. A simple command history with editor

I wrote the initial version of this App to save my time in a project. In the project, I had to running both iPerf and iPerf3 with different options repeatedly. After the project, I figure this App may benefit other folks who are in the same situation, so I have polished the App a little and made it public here. So far I could only test the App on my own nexus phones. In case you see any problem on your device, you are welcome to send me a bug report with the models of your device and Android. In addition, I would like to acknowledge the great work by the iPerf and iPerf3 communities for such wonderful measurement tools.

Based on my own tests and voluntary reports from users (thanks again for sending me the success/failure reports!), I've created the following list of supported and unsupported devices and android versions.
* Nexus 4
* Nexus 5
* Nexus 6 (issues reported for android 5.1.1 but works OK with android 6.0)
* Galaxy S4
* Galaxy S5
* Galaxy S6
* LG G3
* LG G4