Crash fixes.
Merge remote-tracking branch 'upstream/master'
Disable mark-read batching.
Merge pull request #393 from ojiikun/master

Android: Bugfixes, Disable Batching
Switching from SES to Mailgun.
Fixing Sentry.
Merge branch 'master' into tagging

# By Samuel Clay (2) and ojiikun (2)
# Via Samuel Clay (2) and ojiikun (1)
* master:
  Fixing Sentry.
  Switching from SES to Mailgun.
  Disable mark-read batching.
  Crash fixes.