initial implementation of sclockadj2 using adjtimex syscall

initial implementation with and executable and some supporting modules (that should go in /usr/lib/pymodules/python2.7/sdwdate/)

sclockadj sets the interface to PLL and NANO mode. If you run in NANO mode and assume you provide µsec values you're in for a long wait) That is why there is a status mode for the program, so you can check.

    sclocadj2 status [--verbose/-v][--quiet/-q][--set]
The other mode is to set the offset and allows values up to 0.5 sec (500000000 nanoseconds) in non-wait mode and more when specifiying ``--wait`` (which then loops through multiple calls to adjtimex and waits for the kernel to  revert the offset to 0.  

    usage: sclockadj2 offset [-h] [--constant CONSTANT] [--verbose] [--quiet]
                             [--debug] [--wait]
                             nanoseconds

    positional arguments:
      nanoseconds          Nanoseconds to add (substract if negative)

    optional arguments:
      -h, --help           show this help message and exit
      --constant CONSTANT  0 -> fastest autoadjusted for nano/µ sec (default no
                           adjustment)
      --verbose, -v        increase verbosity level
      --quiet, -q          decrease verbosity level
      --debug, -D          Debug messages. Don't change date
      --wait               wait for offset to return to 0


If sclockadj2 is not waiting then a second invocation resets any possible offsets still being processed by the kernel