Improve BLE advertisements.

Split out the fields and make them accessible.
This makes it possible to move more code into Toit, and also gives more
control to users that need more advanced advertisement fields.

examples/ble/advertise.toit

@@ -12,8 +12,16 @@ main:
 
   data := ble.AdvertisementData
       --name="Toit device"
-      --service-classes=[BATTERY-SERVICE]
-      --manufacturer-data=#[0xFF, 0xFF, 't', 'o', 'i', 't']
+      --services=[BATTERY-SERVICE]
+      --manufacturer-specific=#[0xFF, 0xFF, 't', 'o', 'i', 't']
+  if false:
+    // An equivalent way to create the data would use data blocks.
+    data = ble.AdvertisementData [
+      ble.DataBlock.name "Toit device",
+      ble.DataBlock.services-16 [BATTERY-SERVICE],
+      // The company-id is not included here, as its default is #[0xFF, 0xFF].
+      ble.DataBlock.manufacturer-specific "toit",
+    ]
 
   peripheral.start-advertise data
   sleep --ms=1000000

examples/ble/connect.toit

@@ -11,7 +11,7 @@ SCAN-DURATION   ::= Duration --s=3
 
 find-with-service central/ble.Central service/ble.BleUuid:
   central.scan --duration=SCAN-DURATION: | device/ble.RemoteScannedDevice |
-    if device.data.service-classes.contains service:
+    if device.data.contains-service service:
         return device.address
   throw "no device found"
 

examples/ble/heart_rate.toit

@@ -34,8 +34,8 @@ main:
       ? BLE-CONNECT-MODE-NONE
       : BLE-CONNECT-MODE-UNDIRECTIONAL
   peripheral.start-advertise
-      AdvertisementData --name="Toit heart rate demo"
       --connection-mode=connection-mode
+      AdvertisementData --name="Toit heart rate demo"
 
   task::
     simulated-heart-rate := 60

examples/ble/scan.toit

@@ -14,7 +14,7 @@ main:
   addresses := []
 
   central.scan --duration=SCAN-DURATION: | device/ble.RemoteScannedDevice |
-    if device.data.service-classes.contains BATTERY-SERVICE:
+    if device.data.contains-service BATTERY-SERVICE:
       addresses.add device.address
 
   print addresses