DSC Alarm Binding - Added new items

Per a request in the initial pull request #1334 I have added some new switch items in the DSC Alarm binding to help with rule creation.  An example would be the item called *partition_in_alarm* which is turned ON when a partition goes into alarm and turns OFF when the partition is restored.  There are several new items of this type that will make it easier to write rules.  Here is a list of the new items:

* panel_fire_key_alarm
* panel_panic_key_alarm
* panel_aux_key_alarm
* panel_aux_input_alarm
* partition_armed
* partition_entry_delay
* partition_exit_delay
* partition_in_alarm
* zone_in_alarm
* zone_tamper
* zone_fault
* zone_tripped

Also, a new configuration parameter has been added called *pollPeriod* which allows you to adjust the time period between poll requests sent to the DSC Alarm panel.  These changes are reflected in the README.md file.  Hope this helps.

Thanks,
Russell Stephens