Tidy up #7

Removing unused ble_connection_error_page. This page was displayed when
the user pressed the record button in the data collection page while the
glove was not connected; however the button was already disabled when
there was not a glove connected to the app, making this page
logically unreachable.

lib/main.dart

@@ -1,6 +1,5 @@
 
 import 'package:flutter/material.dart';
-import 'package:lsa_gloves/pages/ble_connection_error_page.dart';
 import 'package:lsa_gloves/pages/ble_devices_connection_page.dart';
 import 'package:lsa_gloves/pages/file_content_chart_page.dart';
 import 'package:lsa_gloves/pages/home_page.dart';
@@ -25,7 +24,6 @@ class MyApp extends StatelessWidget {
       routes: {
         FileContentChartPage.routeName: (context) => FileContentChartPage(),
         BleGloveConnectionPage.routeName: (context) => BleGloveConnectionPage(),
-        BleConnectionErrorPage.routeName: (context) => BleConnectionErrorPage(),
       },
       title: 'Lengua de señas Argentina',
       theme: ThemeData(

lib/pages/ble_data_collection_page.dart

@@ -1,14 +1,11 @@
 import 'dart:async';
 
 import 'package:animated_text_kit/animated_text_kit.dart';
-import 'package:flutter/cupertino.dart';
-import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:lsa_gloves/connection/ble/bluetooth_backend.dart';
 import 'package:lsa_gloves/datacollection/measurements_collector.dart';
 import 'package:lsa_gloves/datacollection/measurements_listener.dart';
 import 'package:lsa_gloves/model/glove_measurement.dart';
-import 'package:lsa_gloves/pages/ble_connection_error_page.dart';
 import 'package:provider/provider.dart';
 import 'package:simple_timer/simple_timer.dart';
 import 'dart:developer' as developer;
@@ -160,17 +157,10 @@ class _BleDataCollectionState extends State<BleDataCollectionPage>
 
   void _startRecording(BluetoothBackend bluetoothBackend) {
     developer.log('startRecording');
-    if (bluetoothBackend.connectedDevices.isEmpty) {
-      developer.log('Cant start recording! No devices connected.');
-      Navigator.of(context).push(MaterialPageRoute(
-          builder: (context) => BleConnectionErrorPage(),
-          maintainState: false));
-    } else {
       bluetoothBackend.sendStartDataCollectionCommand();
       _measurementsCollector.startCollecting(
           this.selectedGesture, bluetoothBackend.dataCollectionCharacteristics);
       _isRecording = true;
-    }
   }
 
   void _stopRecording(BluetoothBackend bluetoothBackend) async {