yui/yui3 — pull request #876 by Satyam (2013-06-15 11:22:22+00:00)
Title: Improved the handling of string formatters and `emptyCellValue`

* Fixes issue https://github.com/yui/yui3/issues/843
* Makes handling of empty values consistent. Different criteria were used to evaluate that when applying the string formatter or the `emptyCellValue`. Now the use of a string formatter or the `emptyCellValue` are mutually exclusive, leaving no ambiguous cases in between.
* The protected instance property `_emptyValues` has been added to avoid hardcoding what should be considered empty or missing values.
* String template formatting has been relegated to a `stringTemplate` formatting function in the `BodyView.Formatters` hash of functions.