feat(dropdown): added exportAs to dropdown directives (#785)

* Added exportAs to dropdown directives

* Added 'bs-*' prefix

* updated dropdown docs

* prefix typo fix

Author: tiagoroldao

components/dropdown/dropdown-menu.directive.ts

@@ -1,7 +1,10 @@
 import {Directive, ElementRef, Host, OnInit, HostBinding} from '@angular/core';
 import {DropdownDirective} from './dropdown.directive';
 
-@Directive({selector: '[dropdownMenu]'})
+@Directive({
+  selector: '[dropdownMenu]',
+  exportAs: 'bs-dropdown-menu'
+})
 export class DropdownMenuDirective implements OnInit {
   public dropdown:DropdownDirective;
   public el:ElementRef;

components/dropdown/dropdown-toggle.directive.ts

@@ -8,7 +8,10 @@ import {global} from '@angular/core/src/facade/lang';
 const MouseEvent = (global as any).MouseEvent as MouseEvent;
 /* tslint:enable */
 
-@Directive({selector: '[dropdownToggle]'})
+@Directive({
+  selector: '[dropdownToggle]',
+  exportAs: 'bs-dropdown-toggle'
+})
 export class DropdownToggleDirective implements OnInit {
   @HostBinding('class.disabled')
   @Input() public isDisabled:boolean = false;

components/dropdown/dropdown.directive.ts

@@ -4,7 +4,10 @@ import {
 } from '@angular/core';
 import {dropdownService, NONINPUT} from './dropdown.service';
 
-@Directive({selector: '[dropdown]'})
+@Directive({
+  selector: '[dropdown]',
+  exportAs: 'bs-dropdown'
+})
 export class DropdownDirective implements OnInit, OnDestroy {
   @HostBinding('class.open')
   @Input()

components/dropdown/readme.md

@@ -20,7 +20,10 @@ import { DROPDOWN_DIRECTIVES } from 'ng2-bootstrap/components/dropdown';
 ### Annotations
 ```typescript
 // directive Dropdown
-@Directive({ selector: '[dropdown]' })
+@Directive({
+  selector: '[dropdown]',
+  exportAs: 'bs-dropdown'
+})
 export class Dropdown implements OnInit, OnDestroy {
   @HostBinding('class.open')
   @Input() public get isOpen():boolean {}
@@ -32,7 +35,10 @@ export class Dropdown implements OnInit, OnDestroy {
 }
 
 // directive DropdownToggle
-@Directive({ selector: '[dropdownToggle]' })
+@Directive({ 
+  selector: '[dropdownToggle]',
+  exportAs: 'bs-dropdown-toggle'
+})
 export class DropdownToggle implements OnInit {
   @HostBinding('class.disabled')
   @Input() public isDisabled:boolean = false;