Add guards for unsafe dereferencing (ref #2687)#2757

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jacobq wants to merge 2 commits intoplotly:masterfrom

jacobq:fix-draw-data-exception

Commits on Jun 27, 2018

Add guards for unsafe dereferencing (ref #2687)
jacobq
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Commits on Jun 28, 2018

Fix typo from last commit: no '!'
jacobq
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