minor: fixes for benchmarks and byte buffer defaults

bin/standard_benchmark

@@ -1,8 +1,11 @@
 #!/usr/bin/env ruby
+#$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
 #
 # Note: Ruby 1.9 is faster than 1.8, as expected.
+# This suite will be run again the installed version of ruby-mongo-driver.
+# The c-extension, mongo_ext, will be used if installed.
 
-$LOAD_PATH[0,0] = File.join(File.dirname(__FILE__), '..', 'lib')
+require 'rubygems'
 require 'mongo'
 
 include Mongo

lib/mongo/util/byte_buffer.rb

@@ -21,7 +21,7 @@ class ByteBuffer
 
   def initialize(initial_data=[])
     @buf    = initial_data
-    @cursor = 0
+    @cursor = @buf.length
     @order  = :little_endian
     @int_pack_order    = 'V'
     @double_pack_order = 'E'