Android Composite ADB Interface Windows 8 driver for iRulu U2?
Answering my own question:

After much search I found this post by Koushik Dutta who kindly shared his own developed Universal ADB Driver.

In there I found the installer (UniversalAdbDriverSetup6.msi) and the source code for it.

After running it, my iRulu U2 is now recognized by Device Manager as HTC Android Interface: