#3 Refactored Chip Info into a Structure

[Robert James Kaes]

Rather than passing the chip id, signature,
program_memory_size, and eeprom_memory_size around, I
created a structure to encapsulate those variables.
This refactoring is also in anticipation of needing
additional variables when I get around to fixing the
programming code to handle chips like the ATtiny2313
that require a "page" programming method.

Re-ordered some of the while() loops into do..while
loops. I believe this change simplifies the code
(namely by removing the need for tracking boolean flags.)

Refactored the chip signature check code into it's own
function.

[Robert James Kaes]