Kill Bill currency conversion plugin apis

'com.ning.billing.plugin:killbill-plugin-api-currency:0.6.0'

<dependency>
	<groupId>com.ning.billing.plugin</groupId>
	<artifactId>killbill-plugin-api-currency</artifactId>
	<version>0.6.0</version>
</dependency>

<dependency org="com.ning.billing.plugin" name="killbill-plugin-api-currency" rev="0.6.0"/>

"com.ning.billing.plugin", "killbill-plugin-api-currency", "0.6.0"