DataTable->addRow now automatically casts input strings to Date values if the column expects a date
ValueType mismatch exception message now displays the ValueType name instead of its ID; it's easier to tell what kind of type is expected.
DataTable->addRow now implicitly casts strings to NumberValue or BooleanValue columns
Added tests for auto casting "true" and "false" strings to boolean
Added type casting for common situations where strings can easily be converted to other types