This adds a variable length dummy variable at the front of the EEPROM
when we erase it, which has the effect of moving the location of any
hot variables within the EEPROM. This should improve EEPROM
life. Thanks to Mike for the implementation.
Pair-Programmed-With: Mike Smith
git-svn-id: https://arducopter.googlecode.com/svn/trunk@3234 f9c3cf11-9bcb-44bc-f272-b75c42450872