Fixes for pbi paths and update to 1.5.1 php front end

vnstat.inc changes:
Updated vnstat_php_front end to 1.5.1-updated
Added checks for i386 & amd64 pbi paths 
If file_exists create links for i386 & amd64 paths
Move pfsense style to external themes for 1.5.1
updated vnstat2.xml for new 1.5.1-updated additional files filename

Here is the updated vnstat-php-front with the correct internal pathnames! You will have to change the internal compressed folder on the git source if you choose to download my 1.5.1-updated release instead of using this link below:

http://www.sendspace.com/file/0py5vt

Here is the changes shown on my fork:

https://github.com/parawizard/vnstat-php-frontend