Change all "Sponsor" to "Donate"

[kmcurry]

Sponsor implies a promise of something in return for a contribution. We are not promising anything in return. We will prominently thank them in public. We can articulate what we mean by "prominently thank" but it's not a contract, ex:

• logo on web site
• logo on mailers
• signage at events
• public thank you during event and in social media

[kmcurry]

Fixed in 846639f