Added Span support to Webencoders with direct encoding#338

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gfoidl wants to merge 8 commits intodotnet:masterfrom

gfoidl:webencoders-direct-encode

Commits on Jun 19, 2018

Included .NET Core 2.2 in multi-targeting
gfoidl
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Commits on Jun 20, 2018

Rearranged the #if to make it more readable
gfoidl
committed