Add feature analysis for blockrs

Author: jmcph4

docs/PRIOR_ART.md

@@ -12,19 +12,19 @@
 
 | Functionality                                                                            | blockrs | lazy-etherscan | ethscan | Blocktop |
 |------------------------------------------------------------------------------------------|:-------:|:--------------:|:-------:|:--------:|
-| Display the block numbers of the latest blocks                                           |         |                |         |    ✅    |
-| Identify who built a block (including locally built blocks)                              |         |                |         |    ✅    |
-| Display gas price of most recent blocks                                                  |         |                |         |    ✅    |
-| Display gas limit of most recent blocks                                                  |         |                |         |    ✅    |
-| Store block headers to a local SQLite database on disk                                   |         |                |         |    ✅    |
-| Store block headers to a local SQLite database in memory                                 |         |                |         |    ✅    |
-| Operate headlessly                                                                       |         |                |         |    ✅    |
-| Plot gas usage of most recent blocks as a barchart                                       |         |                |         |    ✅    |
-| Connect to an Ethereum EL node via Websockets                                            |         |                |         |    ✅    |
-| Connect to an Ethereum EL node via IPC (i.e., Unix sockets)                             |         |                |         |    ✅    |
-| Open a block on Etherscan in the default system web browser                             |         |                |         |    ✅    |
-| Open a transaction on Etherscan in the default system web browser                       |         |                |         |    ✅    |
-| Display details of a particular block                                                    |         |                |         |    ✅    |
-| Display details of a particular transaction                                              |         |                |         |    ✅    |
-| Write information about the state of the index to standard output                        |         |                |         |    ✅    |
+| Display the block numbers of the latest blocks                                           |    ✅   |                |         |    ✅    |
+| Identify who built a block (including locally built blocks)                              |    ❌   |                |         |    ✅    |
+| Display gas price of most recent blocks                                                  |    ❌   |                |         |    ✅    |
+| Display gas limit of most recent blocks                                                  |    ❌   |                |         |    ✅    |
+| Store block headers to a local SQLite database on disk                                   |    ❌   |                |         |    ✅    |
+| Store block headers to a local SQLite database in memory                                 |    ❌   |                |         |    ✅    |
+| Operate headlessly                                                                       |    ❌   |                |         |    ✅    |
+| Plot gas usage of most recent blocks as a barchart                                       |    ❌   |                |         |    ✅    |
+| Connect to an Ethereum EL node via Websockets                                            |    ❌   |                |         |    ✅    |
+| Connect to an Ethereum EL node via IPC (i.e., Unix sockets)                              |    ❌   |                |         |    ✅    |
+| Open a block on Etherscan in the default system web browser                              |    ❌   |                |         |    ✅    |
+| Open a transaction on Etherscan in the default system web browser                        |    ❌   |                |         |    ✅    |
+| Display details of a particular block                                                    |    ❌   |                |         |    ✅    |
+| Display details of a particular transaction                                              |    ❌   |                |         |    ✅    |
+| Write information about the state of the index to standard output                        |    ❌   |                |         |    ✅    |