Use strict Base64 encoding to prevent bad requests.

lib/proxifier/proxies/http.rb

@@ -8,7 +8,7 @@ module Proxifier
 
       socket << "CONNECT #{host}:#{port} HTTP/1.1\r\n"
       socket << "Host: #{host}:#{port}\r\n"
-      socket << "Proxy-Authorization: Basic #{["#{user}:#{password}"].pack("m").chomp}\r\n" if user
+      socket << "Proxy-Authorization: Basic #{Base64.strict_encode64("#{user}:#{password}").chomp}\r\n" if user
       socket << "User-Agent: #{user_agent}\r\n" if user_agent
       socket << "\r\n"