Could you remove the SOftI2CMaster_ folder, which seems unnecessary anyway?
When building (at least for ESP8266 chips), the Arduino IDE wants to compile every file, even if they are not needed. When it reaches
thirdparty libraries/SoftI2CMaster_/SoftI2CMaster.cpp, it complains about not finding <util/delay.h>.
After I removed the whole SoftI2CMaster_ folder, everything works perfectly.
For future users who would like a working out-of-the-box experience, I guess you could remove this folder. (sorry for not making a pull request, I don't know how to user mercurial :-( )