Bolt upgrade

[lkysow]

Takes @amasover's commits from #980 and merges with master. Closes #974.

[codecov]

Codecov Report

Merging #992 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #992   +/-   ##
=======================================
  Coverage   72.03%   72.03%           
=======================================
  Files          65       65           
  Lines        5339     5339           
=======================================
  Hits         3846     3846           
  Misses       1192     1192           
  Partials      301      301           

Impacted Files	Coverage Δ
server/events/db/boltdb.go	74.28% <ø> (ø)

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