I've been following this tutorial to a T. It simply guides the user to program an ATTINY using the Arduino Uno as an ISP. It's been pretty smooth sailing so far.
However, now that I am finally trying to upload the code to the ATTINY, I can't get away from the AVR Dude errors. I have tried resetting it at different times, removing the capacitor between RESET and GROUND, and other troubleshooting methods online and none seem to work.
I'm using a mac currently with IDE v 1.6.0
The errors:
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
Also, make sure the Arduino as isp sketch is uploaded, and the right com port is selected, and auto reset is disabled on the uno (typically by putting 10uf cap between reset and ground)
The Arduino-Tiny file you downloaded and extracted to the hardware folder in your sketchbook.
The core contains pin and board definitions. 1.0.x cores are not compatible with 1.6.x, and vice versa. A core that takes advantage of 1.6.x can also use submenus so you don't have to modify boards.txt, but instead pick the options from menus. (the cores linked in my sig do that, but don't have support for board manager easy installation yet)