Peplink OAuth

[undeadindustries]

Please add the below token URL to brokenAuthHeaderProviders in token.go
https://api.ic.peplink.com/api/oauth2/token

[bradfitz]

For now, use:
https://godoc.org/golang.org/x/oauth2#RegisterBrokenAuthHeaderProvider

But also, I'm working on killing it and making this all automatic in #111 and CL:
https://go-review.googlesource.com/c/oauth2/+/157820

So I'll close this for now.