Properly handle only one child Td in a Tr.

Because of React's (silliness)[1] with the type of children, checking
if the children was an array failed when there was only one child, so
data wasn't pulled from it.

This fixes #53

[1] http://facebook.github.io/react/docs/top-level-api.html#react.children
Merge pull request #79 from glittershark/53/tr-with-one-td

Properly handle only one child Td in a Tr.