Issue #1334816 by rszrama: add the base rate to a flat rate's extra description on the admin overview.

Issue #1612702 follow-up by rszrama: only alter the checkout form when we know for certain a default flat rate service has been set.

Issue #1612702 by rszrama, kotnik: add support for designating or unsestting the default flat rate service and selecting it on the checkout form via an alter hook.

Issue #1537394 by rszrama: add a weight column to flat rate services that is used to sort the flat rate services.

Issue #1587126 by rszrama: wrap a call to a Commerce Tax API function in a check to ensure the module is enabled.

Issue #1349020 by rfay, rszrama: properly initialize a flat rate service's data array and check for the existence of an include_tax variable in it before unsetting it on save.

Issue #1349024 by rupertj, rfay, rszrama: add a permission specifically for flat rate service administration and check for that or the more generic 'administer shipping' permission when checking access for flat rate service operations.

Move a clear fix to the form actions container instead of a single purpose div that was actually not being included at all necessary times.

Issue #1334826 by rszrama: add a data array to flat rate service definitions and use it to support base rates including VAT.