Provide void* context to all callbacks

[TinkerPhu]

Hi,
I would like to have context pointers as arguments in all callbacks.
E.g. in adition to:

    //------------- Callbacks -------------//
    void setConnectCallback   ( ble_connect_callback_t    fp);
    void setDisconnectCallback( ble_disconnect_callback_t fp);

add context:

   typedef void (*ble_connect_context_callback_t    ) (uint16_t conn_hdl, void*);
   typedef void (*ble_disconnect_context_callback_t ) (uint16_t conn_hdl, uint8_t reason, void*);

    //------------- Callbacks -------------//
    void setConnectCallback   ( ble_connect_context_callback_t    fp, void* context);
    void setDisconnectCallback( ble_disconnect_context_callback_t fp, void* context);

Of course, for compatibility reasons, these functions (and members) would be in addition to the current code.

Would you accept a pull request, if I write the code?

best regards
TinkerPHU