fix: make it easier to extend providers

Author: mattlewis92

projects/angular-calendar/src/modules/common/calendar-angular-date-formatter.provider.ts

@@ -13,7 +13,7 @@ import { getWeekViewPeriod } from './util';
 @Injectable()
 export class CalendarAngularDateFormatter
   implements CalendarDateFormatterInterface {
-  constructor(private dateAdapter: DateAdapter) {}
+  constructor(protected dateAdapter: DateAdapter) {}
 
   /**
    * The month view header week day labels

projects/angular-calendar/src/modules/common/calendar-moment-date-formatter.provider.ts

@@ -30,8 +30,8 @@ export class CalendarMomentDateFormatter
    * @hidden
    */
   constructor(
-    @Inject(MOMENT) private moment: any,
-    private dateAdapter: DateAdapter
+    @Inject(MOMENT) protected moment: any,
+    protected dateAdapter: DateAdapter
   ) {}
 
   /**

projects/angular-calendar/src/modules/common/calendar-native-date-formatter.provider.ts

@@ -14,7 +14,7 @@ import { getWeekViewPeriod } from './util';
 @Injectable()
 export class CalendarNativeDateFormatter
   implements CalendarDateFormatterInterface {
-  constructor(private dateAdapter: DateAdapter) {}
+  constructor(protected dateAdapter: DateAdapter) {}
 
   /**
    * The month view header week day labels

projects/angular-calendar/src/modules/common/calendar-utils.provider.ts

@@ -20,7 +20,7 @@ import { DateAdapter } from '../../date-adapters/date-adapter';
 
 @Injectable()
 export class CalendarUtils {
-  constructor(private dateAdapter: DateAdapter) {}
+  constructor(protected dateAdapter: DateAdapter) {}
 
   getMonthView(args: GetMonthViewArgs): MonthView {
     return getMonthView(this.dateAdapter, args);