Add pagination to tasks

lib/data/repositories/task_repository.dart

@@ -35,9 +35,10 @@ class TaskRepository {
     return taskResponse.data;
   }
 
-  Future<BuiltList<TaskEntity>> loadList(
-      Credentials credentials, int createdAt, bool filterDeleted) async {
-    final url = credentials.url + '/tasks?created_at=$createdAt';
+  Future<BuiltList<TaskEntity>> loadList(Credentials credentials, int page,
+      int createdAt, bool filterDeleted) async {
+    final url = credentials.url +
+        '/tasks?per_page=$kMaxRecordsPerPage&page=$page&created_at=$createdAt';
 
     /* Server is incorrect if client isn't set
     if (filterDeleted) {

lib/redux/task/task_actions.dart

@@ -73,9 +73,10 @@ class LoadTaskActivity {
 }
 
 class LoadTasks {
-  LoadTasks({this.completer});
+  LoadTasks({this.completer, this.page = 1});
 
   final Completer completer;
+  final int page;
 }
 
 class LoadTaskRequest implements StartLoading {}

lib/redux/task/task_middleware.dart

@@ -1,6 +1,7 @@
 // Flutter imports:
 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
+import 'package:invoiceninja_flutter/constants.dart';
 
 // Package imports:
 import 'package:redux/redux.dart';
@@ -284,16 +285,24 @@ Middleware<AppState> _loadTasks(TaskRepository repository) {
     repository
         .loadList(
       state.credentials,
+      action.page,
       state.createdAtLimit,
       state.filterDeletedClients,
     )
         .then((data) {
       store.dispatch(LoadTasksSuccess(data));
 
-      if (action.completer != null) {
-        action.completer.complete(null);
+      if (data.length == kMaxRecordsPerPage) {
+        store.dispatch(LoadTasks(
+          completer: action.completer,
+          page: action.page + 1,
+        ));
+      } else {
+        if (action.completer != null) {
+          action.completer.complete(null);
+        }
+        store.dispatch(LoadVendors());
       }
-      store.dispatch(LoadVendors());
     }).catchError((Object error) {
       print(error);
       store.dispatch(LoadTasksFailure(error));