Remove easy-batch, but observe the batch pattern

[CXwudi]

Since #3, we are only using the reader, processor and writer classes, and manually build and run the batch processing.

Then there is no need to use explicitly easy-batch's reader, processor and writer classes as it introduce too much overhead of wrapping and unwrapping the Record class.

[CXwudi]

Nor do we really need the Record class's order field as we have our own order field in VSongLabel class