title: Is it possible to require visitor get shipping estimate before moving to checkout process?
body: <p>I am currently working on a magento 1.9.1 website, as the title suggest is it possible to require the visitor to enter the postcode details on the estimate box and get shipping. So he must fill this in on the cart page and make a selection before moving on to the checkout process.</p>
  
  <p>By making this a requirement i am removing the select shipping method step later on the process. At present if the postcode is entered and shipping method selected the checkout process will go as it should. However if no postcode is entered I get the no shipping method selected message. So by making it a requirement, i hope to avoid this problem.</p>
  
  <p>I can enable a default shipping method, but as I am using table rate matrix i can not enter a default shipping as the table rates are based on postcodes.</p>
  
  <p>Plus is it possible to send the postcode collected here sent to the billing info page so he does not have to enter it again.</p>
  
  <p>Please advise. Thanks</p>