Measure variables keep their class when shared
Copy identical attributes instead of shared classes
Remove factor check
Upgrade to Roxygen 4.0
Support factorsAsStrings for melt.data.frame
all_identical as a separate function
Refactor measure.attributes computing code out
Some tweaks
Some more tweaks + robustness
Include updated args in melt_check roxygen
Use $ instead of [[
Update NEWS
Merge pull request #41 from kevinushey/master

Preserve classes of measure variables in melt.data.frame (#21)