cran release file

Merge pull request Crunch-io#401 from Crunch-io/document-valuelabels

valuelabels redux

Merge pull request Crunch-io#400 from Crunch-io/document-valuelabels

add doc for showValueLabels

Merge pull request Crunch-io#397 from Crunch-io/deck-docs

some more examples for deck slides

devtools cran-release file

pkgdown site cleanup

seplling

Some more `all()` safety

Version bump for diagnostics

Fix print method for empty folders