Yes, it's the Teensy++ 2.0 from PJRC (thanks PaulS)
Paul Stoffregen, the maker of the teensy, posts under his complete name. I do not. You've got the wrong Paul S. there.
I originally took that approach because I ran into issues trying to get the Arduino IDE to compile multiple .cpp/.h files in the same sketch, way back when I started.
See: How to avoid the quirks of the IDE sketch file pre-preprocessing