New command line LedgerTool. (RIPD-243)

* Retrieve and process summary or full ledgers.
* Search using arbitrary criteria (any Python function).
* Search using arbitrary formats (any Python function).
* Caches ledgers as .gz files to avoid repeated server requests.
* Handles ledger numbers, ranges, and special names like validated or closed.

bin/LedgerTool.py

@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+from ripple.ledger import Server
+from ripple.ledger.Args import ARGS
+from ripple.util.CommandList import CommandList
+
+from ripple.ledger.commands import Info, Print
+
+_COMMANDS = CommandList(Info, Print)
+
+if __name__ == '__main__':
+    server = Server.Server()
+    args = list(ARGS.command)
+    _COMMANDS.run_safe(args.pop(0), server, *args)