Fix various minor linearization script issues

- The last-timestamp-encountered variable wasn’t being used properly. Rewrite code to properly allow for new blockchain files to be written when split by month.
- Properly set a blockchain file’s access and modify times.
- Add a “debug output” option to quiet certain output that might not always be desirable.
- Update the README.

contrib/linearize/example-linearize.cfg

@@ -1,4 +1,3 @@
-
 # bitcoind RPC settings (linearize-hashes)
 rpcuser=someuser
 rpcpassword=somepassword
@@ -21,6 +20,9 @@ input=/home/example/.bitcoin/blocks
 #genesis=000000000933ea01ad0ee984209779baaec3ced90fa3f408719526f8d77f4943
 #input=/home/example/.bitcoin/testnet3/blocks
 
+# "output" option causes blockchain files to be written to the given location,
+# with "output_file" ignored. If not used, "output_file" is used instead.
+# output=/home/example/blockchain_directory
 output_file=/home/example/Downloads/bootstrap.dat
 hashlist=hashlist.txt
 
@@ -29,3 +31,12 @@ out_of_order_cache_sz = 100000000
 
 # Do we want the reverse the hash bytes coming from getblockhash?
 rev_hash_bytes = False
+
+# On a new month, do we want to set the access and modify times of the new
+# blockchain file?
+file_timestamp = 0
+# Do we want to split the blockchain files given a new month or specific height?
+split_timestamp = 0
+
+# Do we want debug printouts?
+debug_output = False