Merge pull request #43 from kevinushey/master

Make sure OBJECT bit is set when 'value' is a factor
Depend on plyr 1.8.1. Closes #44
Use dcast, not cast, in recast.
Closes #45
Update urls
Preserve order of dimnames.
Closes #19
Use new testthat structure
Re-document
Code outside link, not inside :(
Tweak news
Add r cmd check notes
Bump version
Fix license typo
Bump version