The major change to integrate the patch has been:
* Updating the arguments for `rlp.EncodeToBytes`. This function accepts interfaces, but since the last update, it is better to pass in a pointer to the function.
* From the Ethereum Release Notes: "
Compatibility note about `core/types`: For optimization purposes, `types.Header` and other types in this package now implement the `rlp.Encoder` interface. This change can cause incompatibilities because the new method is implemented with pointer receiver. Attempting to RLP-encode unadressable (i.e. non-pointer) values of type `Header` does not work anymore and will result in an error."
* Instead of just updating all the headers. I have updated all parameters for the `rlp.EncodeToBytes` to be pointers instead of values.
__Please take a close look at the updates__. The functions won't fail if a non-pointer is passed (in most cases), but we could be unexpected behaviors.
This commit decouples knownGaps and Indexer. All knownGaps logic is in its own file. This makes testing and maintainability easier.
We have also removed all efforts to check the `lastProcessedblock` - This is because we won't ever run into this issue (hyptothetically), because geth won't let it happen.
