move port creation to Erlang to fix issue #9

With R16B changes related to locking within the area of port drivers seemed
to result in the syslog driver hanging on the driver_create_port call. To
avoid this, move port creation and closing from C into Erlang. Rework the
driver control interface to simplify the open call to just the setting of
the logopt and facility on a new port. Remove the opening and closing of a
port in the gen_server init and terminate as that port is no longer needed
to communicate with the driver. Move the open call out of the gen_server
and do it in the caller's process instead.
Merge pull request #11 from vinoski/sbv-r16

move port creation to Erlang to fix issue #9
Roll version 1.0.2
Improve syslog module

* Add typespecs
* Add types
* Expose priority/1, facility/1, and openlog_opt/1 for validation
* Add guards to catch errors with priority/1, facility/1, and openlog_opt/1
* Fix code_change/3 bug
Merge pull request #14 from okeuday/master

Improve syslog module
Simplify syslog module usage

* It seems like lager_syslog must require that either:
  1) syslog:start/0 or syslog:start_link/0 was called
  2) syslog_drv.so is in the PATH environment variable for
     erlang:open_port/2 to find as a port driver
  Both of these options have nothing to do currently with starting
  syslog as an application.  This all seems odd, so I just added a
  load/0 function and an unload/0 function to make it easier to use the
  port driver without relying on an extra Erlang process that sits idle
  or the PATH environment variable's extra entry.
Expose logopt/1 as openlog_opts/1 for validation of syslog input.
Merge pull request #15 from okeuday/master

Simplify syslog module usage
Merge pull request #1 from Vagabond/master

Merge upstream