Branch dev-cmake updated

[Thomas K]

Hi,

one info for the cmake branch on dev-cmake: I have updated it because of 
2 fixes.

One is a cmake configuration fix: targets not found if avr-gcc isn't 
installed

The second is a fix for newer gcc versions (thanks to Joel Truher for 
pointing out this) on gtest. Unfortunately we'll lost the possibility to 
test protected and private variables and methods on gtest. But there is 
no other simple solution.

cu, Thomas