Basic support for EAC documents (e.g. German Identification Card)

-new files armsrc/epa.[ch] for ePA (electronic "Personalausweis") related functions
    -Offers elementary functions (EPA_PACE_MSE_Set_AT etc.)
    -Also offers one new USB command: EPA_PACE_Collect_Nonce
-created new command subtree in client: client/hfepa.[ch] ("hf epa")
    -offers "hf epa cnonces" (collect encrypted PACE nonces)
-more to come

armsrc/appmain.c

@@ -714,6 +714,9 @@ void UsbPacketReceived(uint8_t *packet, int len)
 		case CMD_SIMULATE_TAG_ISO_14443a:
 			SimulateIso14443aTag(c->arg[0], c->arg[1], c->arg[2]);  // ## Simulate iso14443a tag - pass tag type & UID
 			break;
+		case CMD_EPA_PACE_COLLECT_NONCE:
+			EPA_PACE_Collect_Nonce(c, &ack);
+			break;
 			
 		case CMD_READER_MIFARE:
 			ReaderMifare(c->arg[0]);