Brandon Long authored Jun 26, 2018 and Kevin J. McCarthy committed Jul 16, 2018

Move token refresh commands to their own config variables. Consolidate
code for refreshing tokens and generating the SASL OAUTHBEARER
argument in account.c. Add support for OAUTHBEARER to pop.

Fix pop_auth_oauth() mutt_from_base64() call from 1.10.1 release.