Patch fixes for battle and campaign creator beta

To access the beta right click on the game in the library and press properties, then navigate to the beta tab and select "public_beta" in the dropdown. You may have to restart steam if the game does not start downloading the beta.

• Fixed issues where downloaded content would not show up in the campaigns list
  
• Added tabs for different type of content in the campaigns menu
  
• Added icons for different type of content in the workshop browser
  
• Loading downloaded battles in sandbox mode now displays the correct image