timeutils: add functions to add, compare, rename elapsed_* functions

Signed-off-by: Michael Heimpold <mhei@heimpold.de>
Do not use struct timespec to declare the timestamp field, it's platform dependend and varies in size

Signed-off-by: Michael Heimpold <mhei@heimpold.de>
Provide received magic number and version in debug message

Signed-off-by: Michael Heimpold <mhei@heimpold.de>