Currency 7.x-2.x compatibilty

This module makes calls to old currency functions that are no longer present in the 7.x-2.x branch:

currency_api_get_list();
currency_api_get_desc();

This results in PHP fatal errors:

Fatal error: Call to undefined function currency_options_get_list()
Fatal error: Call to undefined function currency_options_get_desc()

This can be fixed by replacing currency_api_get_list() with currency_options(), and currency_api_get_desc() with currency_load().

Patch coming...