Updated to build with Python 3.x -- removed dependency on py-xml (it was
    no longer needed/required.)

Updated to 3.15.7

Release Notes:

HPLIP 3.15.7 - This release has the following changes:
Added Support for the Following New Printers:

- HP Deskjet 1110 Printer
- HP Deskjet 1111 Printer
- HP Deskjet 1112 Printer
- HP DeskJet 2131 All-in-One Printer
- HP Deskjet Ink Advantage 1110 Printer
- HP Deskjet Ink Advantage 1115 Printer
- HP Deskjet Ink Advantage 1118 Printer
- HP DeskJet Ink Advantage 2130 All-in_One Printer
- HP DeskJet Ink Advantage 2135 All-in_One Printer
- HP DeskJet Ink Advantage 2138 All-in_One Printer
- HP DeskJet Ink Advantage 3630 All-in-One Printer
- HP DeskJet Ink Advantage 3635 All-in-One Printer
- HP DeskJet Ink Advantage 3636 All-in-One Printer
- HP DeskJet Ink Advantage 3638 All-in-One Printer
- HP DeskJet Ink Advantage 3830 All-in-One Printer
- HP DeskJet Ink Advantage 3835 All-in-One Printer
- HP OfficeJet 3830 All-in-One Printer
- HP OfficeJet 3832 All-in-One Printer
- HP OfficeJet 3834 All-in-One Printer
- HP Officejet 7510 Wide Format All-in-One Printer

Added support for the following new Distro's:

- Debian 8.1
- RHEL 7.1

Issues fixed:

- Removed the duplicate collate option from HP Device Manager
- Traceback error occurs when trying to configure a queue of same name
  but with different IO type
- Traceback error occurs when trying to add unicode file from Device
  Manager on RHEL5

Launchpad fixes:

1464013 - HPLIP installer prompts to set up printers, even when printers
are already set up
1432516 - Insecure binary driver verification (CVE-2015-0839)

(schnoebe)