Fix system events recursive triggering

[mthenw]

What did you implement:

Bug fix for triggering system events by other system events.

How did you implement it:

System events don't emit system events.

Todos:

• Write tests
• Write documentation
• Fix linting errors
• Make sure code coverage hasn't dropped
• Provide verification commands / resources
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: Yes
Is it a breaking change?: NO

[codecov]

Codecov Report

Merging #495 into master will decrease coverage by 0.19%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master     #495     +/-   ##
=========================================
- Coverage    71.2%   71.01%   -0.2%     
=========================================
  Files          37       37             
  Lines        2195     2201      +6     
=========================================
  Hits         1563     1563             
- Misses        571      575      +4     
- Partials       61       63      +2

Impacted Files	Coverage Δ
router/router.go	63.66% <0%> (-1.26%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update fb79ad3...1a64cdb. Read the comment docs.

[sebito91]

LGTM!