Added function journal_print to wrap sd_journal_print

Added a function journal_print that wraps sd_journal_print. This
function is defined in _journal.c and then just imported in its base
state to journal.py.
It takes two arguments: one, one of the LOG_* constants, and the second
being a string to log.
Merge pull request #8 from glittershark/master

Added function journal_print to wrap sd_journal_print