Fixed error: File format not supported! while trying to reassign a column.

[junduck]

Fixes #616

In the original implementation, setter function $setColumnData wrongly assigns selected column to arr directly. If arr is a Series, this results in failure of type check which lead to the confusing "File format not supported" exception.

This fix assigns correct extracted values colunmValuesToAdd to selected columns.

Unit test addColumn pass, no new tests needed for coverage.