More fixes to paypal urls.
Avoid duplicating url query args.
Fixing up require_once paths.
More paypal fixes.  Removed incorrect calls to freeseat_url().
Also fixed up freeseat_url().
Paypal return path works now.
Making sure that the fsp query arg only appears once.
Moved replace_fsp() to freeseat.php.
Merge branch 'master' of https://github.com/cdhassell/freeseat4wp