* [DEV-75] Removed fetchEntryByHash, which was no longer used.
* [DEV-75] Removed a few functions in manager.go that weren't used by anything.
* [DEV-75] checkConnectBlock will soon not accept a utxoViewpoint, so removed the call to view.Tip() so that it could be deleted.
* [DEV-75] Got rid of tips in UtxoViewpoint.
* [DEV-75] Added the full UTXO set to the virtual block.
* [DEV-75] Implemented UTXO-wrangling when adding a new block.
* [DEV-75] Added isCoinbase to utxoEntry creation.
* [DEV-75] Added blockHeight to utxoEntry creation.
* Implemented fetching the fullUTXOSet from the database.
* [DEV-75] Simplified DAGState because almost all of the state in it was unnecessary. Also got rid of dbDAGState.
* [DEV-75] Made the process around adding a new block, UTXO-wise, much safer.
* [DEV-75] Implemented melding the virtual UTXO diff to the database.
* [DEV-75] Fixed utxoSet loading from the wrong bucket.
* [DEV-75] Began pruning utxoviewpoint.go. Replaced FetchUtxoEntry with a fullUTXOSet-based GetUTXOEntry.
* [DEV-75] Removed fetchUtxos.
* [DEV-75] Moved GetUTXOEntry into the virtual block.
* [DEV-75] Updated IndexManager to not use utxoViewpoints.
* [DEV-75] Fixed some bad login in restoreUTXO involving nodeDiffs.
* [DEV-75] Got rid of the UTXO spend journal, which wasn't used anywhere.
* [DEV-75] Moved some STXO-related validation logic out of connectToDAG and into checkConnectBlock.
* [DEV-75] Renamed UtxoXxx to UTXOXxx. Removed a bunch of methods that were no longer used by anything.
* [DEV-75] Another Utxo -> UTXO rename.
* [DEV-75] Removed IsModified from UTXOView, which was not used anywhere.
* [DEV-75] Renamed nodeDiff to provisionalNode. Added a bunch of comments.
* [DEV-75] Removed the test for genesis in pastUTXO, since it can never happen.
* [DEV-75] Wrote tests for errors in pastUTXO.
* [DEV-75] Wrote tests for errors in restoreUTXO.
* [DEV-75] Improved testErrorThroughPatching.
* [DEV-75] Wrote tests for errors in verifyAndBuildUTXO.
* [DEV-75] Used TipHashes instead of tips().hashes(), fixed comments in a few places, and brought back an error return that I erroneously removed.
* [DEV-75] Removed UTXO set logs.
* [DEV-75] Recreated add/remove/contains functions for utxoCollection.
* [DEV-75] Changed newUTXOEntry to use an object initializer.
* [DEV-75] Changed the UTXO bucket version to 1.
* Added a comment that clarifies that the index is not initialized before initDAGState is called.
* [DEV-75] Renamed GetVirtualBlock to VirtualBlock.
* [DEV-75] Removed superfluous variables.
* [DEV-75] Combined connectBlockToParents with updateParentsDiffs.
* [DEV-75] Removed another superfluous variable.
* [DEV-75] In pastUTXO, first fetch transactions from the database and only then add them.
* [DEV-75] Reworded the comment for commit().
* [DEV-75] Made all the connectUTXO subfunctions not BlockDAG methods.
* [DEV-75] Updated the comment for connectUTXO.
* [DEV-75] Updated the comment explaining why we're creating provisionalNodes.
* [DEV-75] Removed a couple of unnecessary calls to toProvisionalNode.
* [DEV-75] Renamed connectUTXO to applyUTXOChanges.
* [DEV-75] Replaced allProvisionalNodes with provisionalNodeSet, an object that holds provisionalNodes for this particular call to applyUTXOChanges.
* [DEV-75] Changed createProvisionalNode to accept a boolean "withParents" instead of relying on the caller to supply the node's parents or an empty set.
* [DEV-75] Made most applyUTXOChanges subfunctions be methods on provisionalNode.
* [DEV-75] Fixed a couple of bad comments.
* [DEV-75] Added descriptive error messages to callers of applyUTXOChanges.
* [DEV-75] Fixed weird English.
* [DEV-75] Replaced DAGState with a slice of DAG tip hashes.
* [DEV-75] In createProvisionalNode, changed withParents to withRelatives to avoid certain kinds of attacks.
* [DEV-75] Renamed createdProvisionalNode to newProvisionalNode.
* [DEV-75] Added precalculating the amount of transactions inside a new block's blue set.
* [DEV-75] Pruned unnecessary variable.
