Added support for PayPal page_style. Closes #283
Remove Reports Default post_parent.

The post_parent = 0 in, would shows only top level posts, which in Payment Errors\Logs would mean that it will not return any payment errors attached(children) to a Payment.
If omitted, all payment errors/logs will be shown and will not affect other requests since they have parent post filter or are top level posts in the first place. 
Merge pull request #737 from vanbo/master

Remove Reports Log Default post_parent. 
Exclude flat rate discounts from edd_get_download_final_price(). This is a weak work around for now, but will work until we revamp discount codes. Closes #741
Added new edd_error_class filter
Fixed discount start date column. #731
added IDs to all P tags on checkout. Closes #739
Don't show discount on receipt if none used. Closes #708
Added new hooks to top and bottom of edit/add discount screens. Closes #706
Fixed pagination in purchase history for #723
Fixed pagination of download history for #723