1.3 -> 1.3.1
-------------
* Fix a problem that pam_ruby-1.3 die by running with non-ruby program.

1.2 -> 1.3
-----------
* PAM.module_dispatch is a new function. (See also sample/simple2.rb)

1.1 -> 1.2
----------
* PAM.syslog is a new module function.
  - PAM.syslog(priority, message)

* new constants for specifying the priority of syslog:
  - PAM::LOG_EMERG
  - ....
  - PAM::DEBUG
  (see also the manual page of `syslog')

* exceptions raised in the pam_ruby is logged by syslog
  with LOG_ERR.

* pam_ruby call the Init_pam(). it is becase Linux-PAM uses the
  dlopen() with RTLD_NOW, so the pam_ruby can't resolve symbols
  defined in the ruby-pam.
