Update linearize scripts.

Break into two steps:
* Generate hash list
* Build data file(s) from local bitcoind blocks/ directory.

This supports building one large bootstrap.dat, or multiple
smaller blocks/blkNNNNN.dat files.

contrib/linearize/example-linearize.cfg

@@ -1,12 +1,16 @@
 
-# bitcoind RPC settings
+# bitcoind RPC settings (linearize-hashes)
 rpcuser=someuser
 rpcpassword=somepassword
 host=127.0.0.1
 port=8332
 
-# bootstrap.dat settings
-netmagic=f9beb4d9
-max_height=279000
-output=bootstrap.dat
+# bootstrap.dat hashlist settings (linearize-hashes)
+max_height=313000
+
+# bootstrap.dat input/output settings (linearize-data)
+netmagic=f9beb4d9
+input=/home/example/.bitcoin/blocks
+output_file=/home/example/Downloads/bootstrap.dat
+hashlist=hashlist.txt