Create an empty metatable for user modules

If a user module is loaded into a global variable the preservation
will restore it to an empty table, wiping out the real module.
Add access to internal data

- initial configuration settings
- column header information
remove unused variable 'seconds_in_minute'
Update the documentation
Merge pull request #15 from bartleusink/unused_variable_seconds_in_minute

remove unused variable 'seconds_in_minute'
Merge pull request #14 from mozilla-services/user_module_metadata

Create an empty metatable for user modules
Merge pull request #16 from mozilla-services/expose_internal_data

Expose internal data
Issue #17 further parse the syslogtag variable
Fix the circular buffer 'get' beyond the end of the buffer

It now returns nil as specified instead of wrapping around to the
beginning of the buffer.
Merge pull request #18 from mozilla-services/parse_syslogtag

Issue #17 further parse the syslogtag variable
Merge pull request #19 from mozilla-services/cbuf_get_beyond_end

Fix the circular buffer 'get' beyond the end of the buffer
Fix the %c grammar to use a space padded month
One more tweak to programname

Don't follow the RFC standard just accept what rsyslog outputs.
Merge pull request #20 from mozilla-services/datetime_c

Fix the %c grammar to use a space padded month
Merge pull request #21 from mozilla-services/rsyslog_programname

One more tweak to programname
new, mostly functional haproxy log grammar