Allow linearization scripts to support hash byte reversal

Currently, the linearization scripts require input hashes to be in one endian form. Add support for byte reversal.

contrib/linearize/README.md

@@ -1,33 +1,43 @@
 # Linearize
-Construct a linear, no-fork, best version of the blockchain.
+Construct a linear, no-fork, best version of the Bitcoin blockchain.
 
 ## Step 1: Download hash list
 
     $ ./linearize-hashes.py linearize.cfg > hashlist.txt
 
 Required configuration file settings for linearize-hashes:
-* RPC: rpcuser, rpcpassword
+* RPC: `rpcuser`, `rpcpassword`
 
 Optional config file setting for linearize-hashes:
-* RPC: host, port
-* Block chain: min_height, max_height
+* RPC: `host`, `port`  (Default: `127.0.0.1:8332`)
+* Blockchain: `min_height`, `max_height`
+* `rev_hash_bytes`: If true, the written block hash list will be
+byte-reversed. (In other words, the hash returned by getblockhash will have its
+bytes reversed.) False by default. Intended for generation of
+standalone hash lists but safe to use with linearize-data.py, which will output
+the same data no matter which byte format is chosen.
 
 ## Step 2: Copy local block data
 
     $ ./linearize-data.py linearize.cfg
 
 Required configuration file settings:
-* "input": bitcoind blocks/ directory containing blkNNNNN.dat
-* "hashlist": text file containing list of block hashes, linearized-hashes.py
-output.
-* "output_file": bootstrap.dat
+* `output_file`: The file that will contain the final blockchain.
       or
-* "output": output directory for linearized blocks/blkNNNNN.dat output
+* `output`: Output directory for linearized blocks/blkNNNNN.dat output.
 
 Optional config file setting for linearize-data:
-* "netmagic": network magic number
-* "max_out_sz": maximum output file size (default `1000*1000*1000`)
-* "split_timestamp": Split files when a new month is first seen, in addition to
-reaching a maximum file size.
-* "file_timestamp": Set each file's last-modified time to that of the
-most recent block in that file.
+* `file_timestamp`: Set each file's last-modified time to that of the most
+recent block in that file.
+* `genesis`: The hash of the genesis block in the blockchain.
+* `input: bitcoind blocks/ directory containing blkNNNNN.dat
+* `hashlist`: text file containing list of block hashes created by
+linearize-hashes.py.
+* `max_out_sz`: Maximum size for files created by the `output_file` option.
+(Default: `1000*1000*1000 bytes`)
+* `netmagic`: Network magic number.
+* `rev_hash_bytes`: If true, the block hash list written by linearize-hashes.py
+will be byte-reversed when read by linearize-data.py. See the linearize-hashes
+entry for more information.
+* `split_timestamp`: Split blockchain files when a new month is first seen, in
+addition to reaching a maximum file size (`max_out_sz`).