This enforces the use of unsigned 64-bit values for time in the duration type,
the timeout framework, the timer session, the userland timer-drivers, and the
alarm framework on all platforms. The commit also adapts the code that uses
these tools accross all basic repositories (base, base-*, os. gems, libports,
ports, dde_*) to use unsigned 64-bit values for time as well as far as this
does not imply profound modifications.
Fixes#3208
