* xcvrd OIR support for Dell S6100/Z9100 switches
Introduced check_interrupts function to handle missed interrupts.
port_dict updated and returned for appropriate OIR events.
Added support for both S6100/Z9100 switches.
* Revamped sfputil.py for PEP8 Standards
( All device-specific files now reside under /device directory in a <vendor-name>/<platform-string>/<hardware-SKU> directory structure in repo.
* Device-specific files are now packaged into a Debian package (sonic-device-data) and are now installed to /usr/share/sonic/device/<platform-string>/<hardware-SKU>/ directory on switch.
