ULP Timestamp and support for structs

[fededim]

Solved also this, the assembly code was fine, the problem was in the printf for 64 bit types you have to use %lld

printf("ULP RTC %lld C++ RTC %lld Diff %lld\n", ulprtc,cpprtc,cpprtc-ulprtc);

Also the difference which was always reported as zero is now printed. Ok now I concentrate on I2C part.