use binary mode for payload's temp file. Fixes #117.

history.md

@@ -3,6 +3,7 @@
 - added Response.to_str and AbstractResponse.to_i to improve semantic and compatibility
 - multipart Payloads ignores the name attribute if it's not set (patch provided by Tekin Suleyman)
 - correctly takes into account user headers whose keys are strings (path provided by Cyril Rohr)
+- use binary mode for payload temp file
 
 # 1.4.2
 

lib/restclient/payload.rb

@@ -116,6 +116,7 @@ module RestClient
         b = "--#{boundary}"
 
         @stream = Tempfile.new("RESTClient.Stream.#{rand(1000)}")
+        @stream.binmode
         @stream.write(b + EOL)
 
         if params.is_a? Hash