Add unrolling separator & field name map to logging framework.

- When a log record is being "unrolled" (sub-records flattened
   out into a single record), it's now possible to choose the
   character/string to separate the outer name from the inner
   name.  This can be used to work around the problems
   with ElasticSearch 2.0 not supporting dots "." in field names.
   This value can be provided per-filter as well as a global
   default value.
 - Log fields can be renamed by providing a table per-filter
   (or a global default) to rename fields for any log writer.
   The name translation is performed after unrolling so the
   value in the field name table must match whatever is being
   used to separate field names.

   For example if the unrolling separator was set to "*":
	redef Log::default_unrolling_sep = "*";

   The field name map would need to reflect it:
	redef Log::default_field_name_map = {
		["id*orig_h"] = "src",
		["id*orig_p"] = "src_port",
		["id*resp_h"] = "dst",
		["id*resp_p"] = "dst_port",
	};

testing/btest/scripts/base/frameworks/logging/field-name-map.bro

@@ -0,0 +1,11 @@
+# @TEST-EXEC: bro -b -r $TRACES/wikipedia.trace %INPUT
+# @TEST-EXEC: btest-diff conn.log
+
+@load base/protocols/conn
+
+redef Log::default_field_name_map = {
+	["id.orig_h"] = "src",
+	["id.orig_p"] = "src_port",
+	["id.resp_h"] = "dst",
+	["id.resp_p"] = "dst_port",
+};

testing/btest/scripts/base/frameworks/logging/unrolling_sep.bro

@@ -0,0 +1,6 @@
+# @TEST-EXEC: bro -b -r $TRACES/wikipedia.trace %INPUT
+# @TEST-EXEC: btest-diff conn.log
+
+@load base/protocols/conn
+
+redef Log::default_unrolling_sep = "_";

testing/btest/scripts/base/frameworks/logging/unrolling_sep_and_field_name_map.bro

@@ -0,0 +1,15 @@
+# This tests the order in which the unrolling and field name 
+# renaming occurs.
+
+# @TEST-EXEC: bro -b -r $TRACES/wikipedia.trace %INPUT
+# @TEST-EXEC: btest-diff conn.log
+
+@load base/protocols/conn
+
+redef Log::default_unrolling_sep = "*";
+redef Log::default_field_name_map = {
+	["id*orig_h"] = "src",
+	["id*orig_p"] = "src_port",
+	["id*resp_h"] = "dst",
+	["id*resp_p"] = "dst_port",
+};