Make partners section for logos on homepage

[sethwoodworth]

Include:

• Unglue.it
• RTC
• Travis-ci (get permission from Dan)
• NYPL (ask permission from James/Micah)
• DPLA (ask Rachel Frick)
• Github (ask Arfon)
• Gutenberg (ask Greg)

Suggestions @rdhyee @eshellman

[eshellman]

Will correspond with Rachel, Arfon, and NYPL