Improved AVR SPI Programmer connector

I've applied this changes to the `AVR_SPI_PROGRAMMER-1` symbol:
* Renamed pin "5" -> "VCC" (because can be used with different voltages than +5V, for example +3.3V);
* Set pin name to the same values as the cosmetics texts;
* Set pin directions;

I've also edited the `AVR_SPI_PROG2` device to:
* Set the name to the generic "G$1" instead of "A";
* Added the prefix "J".

Congratulations for this great library. I will be happy to help improving it.