Add a Bluetooth Low Energy (BLE) transport type

Libdivecomputer doesn't have built-in support for BLE communication yet,
so this is mainly for future use and custom I/O implementations.

examples/common.c

@@ -98,6 +98,7 @@ static const transport_table_t g_transports[] = {
 	{"usbhid",    DC_TRANSPORT_USBHID},
 	{"irda",      DC_TRANSPORT_IRDA},
 	{"bluetooth", DC_TRANSPORT_BLUETOOTH},
+	{"ble",       DC_TRANSPORT_BLE},
 };
 
 const char *

include/libdivecomputer/common.h

@@ -48,6 +48,7 @@ typedef enum dc_transport_t {
 	DC_TRANSPORT_USBHID    = (1 << 2),
 	DC_TRANSPORT_IRDA      = (1 << 3),
 	DC_TRANSPORT_BLUETOOTH = (1 << 4),
+	DC_TRANSPORT_BLE       = (1 << 5)
 } dc_transport_t;
 
 typedef enum dc_family_t {