Fixed the do_split bug and added a test.

* do_split was having a problem if there was another match
  after the end of the number of separators.  It would only
  return the match up to the point of the next match instead
  of the rest of the string.

src/strings.bif

@@ -225,6 +225,8 @@ Val* do_split(StringVal* str_val, RE_Matcher* re, TableVal* other_sep,
 			}
 
 		Val* ind = new Val(++num, TYPE_COUNT);
+		if ( num_sep >= max_num_sep )
+			offset = end_of_s-s;
 		a->Assign(ind, new StringVal(offset, (const char*) s));
 		Unref(ind);
 

testing/btest/Baseline/bifs.string_splitting/out

@@ -0,0 +1,4 @@
+{
+[2] = Testing Test (http://www.example.com),
+[1] = X-Mailer
+}

testing/btest/bifs/string_splitting.bro

@@ -0,0 +1,9 @@
+#
+# @TEST-EXEC: bro %INPUT >out
+# @TEST-EXEC: btest-diff out
+
+event bro_init()
+	{
+	local a = "X-Mailer: Testing Test (http://www.example.com)";
+	print split1(a, /:[[:blank:]]*/);
+	}