making good progress.  This is the initial commit.  I need to close out some other issues.
merge
merge
removing unneeded vars.
Making major progress!!!  I've got the code back to where it was, but completely decoupled.  Now I need to execute the page building concurrently.
Adding in more concurrency!!!  Link validation and page building now happen concurrently.
removing unused import
Adding debugging statements to AssetManager.
optimizing the logging to only log when an asset is actually transferred.
Adding in more concurrency!!  GroupedAssetTransactions now occur at the same time LinkValidation takes place.
closes #62:  process grouped asset transactions concurrently. enhancement.
closes #61:  validate external URL's concurrently. enhancement.