Version below 4.6.0 does not support DefaultLitePullConsumer

DefaultMQPullConsumer has been instead of by DefaultLitePullConsumer.After I rebase master into my develop branch,some mistakes have occurred.And my company uses version `4.3`

So I run the old version and everything is normal.I'm thing about the compatibility.After reading the documents,I found the following explanation.

Since not all version support `LitePull`.The generality of the code is very poor, and users need to spend a lot of effort merging the code to use the full functionality.
If there is no particularly big improvement, is it necessary to replace way of pull?
There are still many features to be added,some bugs to be fixed. See #63
So I think that resetting the commit of #46 is a good choice.After all of functions are available,It's not too late to replace `CommonPull` by `LitePull` in a new branch or tag.

The issue names DefaultMQPullConsumer, DefaultLitePullConsumer, version 4.3, and commits #46 and #63; begin by tracing where the consumer choice is used and comparing that path with the documented version support. Review the referenced changes and determine which versions must remain compatible; done requires an agreed compatibility behavior validated against the affected versions.

Written by the indexing model from the issue text.