Update the year information at mantis theme dynamically.
    
    - Previously, the year information set in the copyright line at
      bottom.html pointed to 2013 literally. This limit copyright year to
      2013. So, in order for The CentOS Project to hold the copyright for
      the current year, the year information set in the copyright line
      must be dynamic. This commit makes the copyright year dynamic by
      using php scripting inside bottom.html file.