wifi - Moved wifi_ap_t into its own class WiFiAccessPoint

Using a class for this structure is more idiomatic C++, allows
future deprecations, and more flexibility of the internal structure.

Additionally, this matches to design of the SocketAddress class
specific to the network-socket api.

features/net/network-socket/WiFiAccessPoint.cpp

@@ -0,0 +1,37 @@
+#include "network-socket/WiFiAccessPoint.h"
+
+WiFiAccessPoint::WiFiAccessPoint()
+{
+    memset(&_ap, 0, sizeof(_ap));
+}
+
+WiFiAccessPoint::WiFiAccessPoint(nsapi_wifi_ap_t ap)
+{
+    _ap = ap;
+}
+
+const char *WiFiAccessPoint::get_ssid() const
+{
+    return _ap.ssid;
+}
+
+const uint8_t *WiFiAccessPoint::get_bssid() const
+{
+    return _ap.bssid;
+}
+
+nsapi_security_t WiFiAccessPoint::get_security() const
+{
+    return _ap.security;
+}
+
+int8_t WiFiAccessPoint::get_rssi() const
+{
+    return _ap.rssi;
+}
+
+uint8_t WiFiAccessPoint::get_channel() const
+{
+    return _ap.channel;
+}
+

features/net/network-socket/WiFiAccessPoint.h

@@ -0,0 +1,70 @@
+/* WiFiInterface
+ * Copyright (c) 2015 - 2016 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef WIFI_ACCESS_POINT_H
+#define WIFI_ACCESS_POINT_H
+
+#include <string.h>
+#include "network-socket/nsapi_types.h"
+
+/** WiFiAccessPoint class
+ *
+ *  Class that represents a WiFi Access Point
+ *  Common interface that is shared between WiFi devices
+ */
+class WiFiAccessPoint
+{
+    /** WiFiAccessPoint lifetime
+     */
+    WiFiAccessPoint();
+    WiFiAccessPoint(nsapi_wifi_ap_t ap);
+
+    /** Get an access point's ssid
+     *
+     *  @return The ssid of the access point
+     */
+    const char *get_ssid() const;
+
+    /** Get an access point's bssid
+     *
+     *  @return The bssid of the access point
+     */
+    const uint8_t *get_bssid() const;
+
+    /** Get an access point's security
+     *
+     *  @return The security type of the access point
+     */
+    nsapi_security_t get_security() const;
+
+    /** Gets the radio signal strength for the access point
+     *
+     *  @return         Connection strength in dBm (negative value),
+     *                  or 0 if measurement impossible
+     */
+    int8_t get_rssi() const;
+
+    /** Get the access point's channel
+     *
+     *  @return The channel of the access point
+     */
+    uint8_t get_channel() const;
+
+private:
+    nsapi_wifi_ap_t _ap;
+};
+
+#endif

features/net/network-socket/WiFiInterface.h

@@ -20,7 +20,7 @@
 #include <string.h>
 #include "Callback.h"
 #include "network-socket/NetworkInterface.h"
-#include "nsapi.h"
+#include "network-socket/WiFiAccessPoint.h"
 
 /** WiFiInterface class
  *
@@ -29,14 +29,6 @@
 class WiFiInterface: public NetworkInterface
 {
 public:
-    typedef struct wifi_ap {
-        char ssid[33]; /* 32 is what 802.11 defines as longest possible name; +1 for the \0 */
-        uint8_t bssid[6];
-        nsapi_security_t security;
-        int8_t rssi;
-        uint8_t channel;
-    } wifi_ap_t;
-
     /** WiFiInterface lifetime
      */
     virtual ~WiFiInterface() {};
@@ -107,7 +99,7 @@ public:
      * @return          Number of entries in @a, or if @a count was 0 number of available networks, negative on error
      *                  see @a nsapi_error
      */
-    virtual int scan(wifi_ap_t *res, unsigned count) = 0;
+    virtual int scan(WiFiAccessPoint *res, unsigned count) = 0;
 };
 
 #endif

features/net/network-socket/nsapi.h

@@ -25,6 +25,7 @@
 
 // entry point for C++ api
 #include "network-socket/SocketAddress.h"
+#include "network-socket/WiFiAccessPoint.h"
 #include "network-socket/NetworkStack.h"
 
 #include "network-socket/NetworkInterface.h"

features/net/network-socket/nsapi_types.h

@@ -163,6 +163,18 @@ typedef enum nsapi_option {
     NSAPI_RCVBUF,    /*!< Sets recv buffer size */
 } nsapi_option_t;
 
+/** nsapi_wifi_ap structure
+ *
+ *  Structure representing a WiFi Access Point
+ */
+typedef struct nsapi_wifi_ap {
+    char ssid[33]; /* 32 is what 802.11 defines as longest possible name; +1 for the \0 */
+    uint8_t bssid[6];
+    nsapi_security_t security;
+    int8_t rssi;
+    uint8_t channel;
+} nsapi_wifi_ap_t;
+
 
 /** nsapi_stack structure
  *