Update mantis-1.1.8-5.el5 visual style customization.
    
    - Previously, images affecting Mantis visual style were stored inside
      the images/ directory at Mantis directory structure. Using such
      configuration in a shared environment isn't appropriate because it
      duplicate places to maintain. This update moves all images affecting
      Mantis visual style from Mantis directory structure to
      /var/www/webenv/images directory structure a common place for web
      applications to share images affecting their visual style.
    
    - Previously, the logo image used in this customization was composed
      of The CentOS Logo and The Website Logo, both in one image. This
      update splits the logo image in two separate images, one for The
      CentOS Logo and other for The Website Logo in order for web browsers
      to load The CentOS Logo only the first time and, for further
      requests, use the browser cache for sub-sequent requests. This is
      faster and doesn't require to make any request to the web server.
    
    - Update README file to describe configuration changes.