parts: Bug fix for i2c_eeprom part

    Fixes:

    > Part address and mask weren't set in i2c_eeprom_init. The
      virtual part responded to all addresses.
    > Mask required inverting to function as per the description in
      i2c_eeprom.h
Makefile: fix for OSX bash variable substitution

This was generating a bad config file

Signed-off-by: Michel Pollet <buserror@gmail.com>
cores; 128rfr2, tiny84 and megax8, temp fix for bad arv-libc headers

Temporary, to make the build work. Seems the latest avr-libc in debian
is rather mangled.

Signed-off-by: Michel Pollet <buserror@gmail.com>
Merge pull request #78 from dougszumski/i2c_eeprom_bugfix

parts: Bug fix for i2c_eeprom part
twi: Clear TWSTO bit after STOP condition transmitted

> This change fixes a problem where a TWI driver polling the
  TWSTO bit would run on the real device but not simavr.

> More detail in for example p188 of the ATMega32A datasheet
  (rev 815D-AVR-10/2013).
examples: Removed unused code in ssd1306 demo
Merge pull request #80 from dougszumski/avr_twi_bugfix

twi: Clear TWSTO bit after STOP condition transmitted
Merge pull request #81 from dougszumski/ssd1306_demo

examples: Removed unused code in ssd1306 demo