Update gen-typescript-declarations and generate constructor types (#5281)

* Update gen-typescript-declarations and generate constructor types

* Fix package-lock file

* Specify NPM version in Travis file

Author: TimvdLippe

.travis.yml

@@ -8,6 +8,8 @@ addons:
 cache:
   directories:
   - node_modules
+before_install:
+- npm i -g [email protected] # Make sure we use the latest version of NPM for correct lock files
 before_script:
 - npm install -g bower gulp-cli@1
 - bower install