Rework electrumx_rpc; add "query" command

rpc-interface.rst

@@ -23,7 +23,7 @@ Add a peer to the peers list.  ElectrumX will schdule an immediate
 connection attempt.  This command takes a single argument: the peer's
 "real name" as it used to advertise itself on IRC::
 
-  $ ./electrumx_rpc add_peer "ecdsa.net v1.0 s110 t"
+  $ electrumx_rpc add_peer "ecdsa.net v1.0 s110 t"
   "peer 'ecdsa.net v1.0 s110 t' added"
 
 daemon_url
@@ -48,7 +48,7 @@ disconnect
 Disconnect the given session IDs.  Session IDs can be seen in the logs
 or with the `sessions`_ RPC command::
 
-  $ ./electrumx_rpc disconnect 2 3
+  $ electrumx_rpc disconnect 2 3
   [
       "disconnected 2",
       "disconnected 3"
@@ -161,6 +161,30 @@ Peer data is obtained via a peer discovery protocol documented
   [...]
   electroncash.checksum0.com     good   50001 50002 ElectrumX 1.2.1    0.9  1.1          07h 30m 40s 07h 30m 41s     0                 peer 149.56.198.233
 
+query
+-----
+
+Run a query of the UTXO and history databases against one or more
+addresses or hex scripts.  `--limit <N>` or `-l <N>` limits the output
+for each kind to that many entries.  History is printed in blockchain
+order; UTXOs in an arbitrary order.
+
+For example::
+
+  $ electrumx_rpc query --limit 5 76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac
+  Script: 76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac
+  History #1: height 123,723 tx_hash 3387418aaddb4927209c5032f515aa442a6587d6e54677f08a03b8fa7789e688
+  History #2: height 127,280 tx_hash 4574958d135e66a53abf9c61950aba340e9e140be50efeea9456aa9f92bf40b5
+  History #3: height 127,909 tx_hash 8b960c87f9f1a6e6910e214fcf5f9c69b60319ba58a39c61f299548412f5a1c6
+  History #4: height 127,943 tx_hash 8f6b63012753005236b1b76e4884e4dee7415e05ab96604d353001662cde6b53
+  History #5: height 127,943 tx_hash 60ff2dfdf67917040139903a0141f7525a7d152365b371b35fd1cf83f1d7f704
+  UTXO #1: tx_hash 9aa497bf000b20f5ec5dc512bb6c1b60b68fc584d38b292b434e839ea8807bf0 tx_pos 0 height 254,148 value 5,500
+  UTXO #2: tx_hash 1c998142a5a5aae6f8c1eab245351413fe8d4032a3f14345f9943a0d0bc90ec0 tx_pos 0 height 254,161 value 5,500
+  UTXO #3: tx_hash 53345491b4829140be53f30079c6e4556a18545343b122900ebbfa158f9ca97a tx_pos 0 height 254,163 value 5,500
+  UTXO #4: tx_hash c71ad947ac46af217da3cd5521113cbd03e36ddada2b4452afe6c15f944d2529 tx_pos 0 height 372,916 value 1,000
+  UTXO #5: tx_hash c944a6acac054275a5e294e746d9ce79f6dcae91f3b4f5a84561aee6404a55b3 tx_pos 0 height 254,148 value 5,500
+  Balance: 17.8983303 BCH
+
 reorg
 -----