(chore) Fix rxjs dependency, moved it to dev dep

.travis.yml

@@ -5,6 +5,7 @@ node_js:
 
 before_install:
 - npm install -g npm@latest
+- npm install rxjs@5.0.0-beta.6
 
 script:
 - npm test

ng2-file-upload.ts

@@ -1,5 +1,3 @@
-/// <reference path="node_modules/@angular/platform-browser/index.d.ts" />
-
 export * from  './components/file-upload/file-select';
 export * from  './components/file-upload/file-drop';
 export * from  './components/file-upload/file-uploader';

package.json

@@ -28,7 +28,6 @@
   },
   "homepage": "https://github.com/valor-software/ng2-file-upload#readme",
   "dependencies": {
-    "rxjs": "5.0.0-beta.6"
   },
   "peerDependencies": {
     "@angular/common": "^2.0.0-rc.1",
@@ -68,7 +67,7 @@
     "raw-loader": "0.5.1",
     "reflect-metadata": "0.1.2",
     "require-dir": "0.3.0",
-    "rxjs": "^5.0.0-beta.6",
+    "rxjs": "5.0.0-beta.6",
     "ts-loader": "0.8.2",
     "tslint": "3.9.0",
     "typescript": "1.8.10",