Add TypeScript declarations to iron-a11y-keys. (#45)

* Generate minimal package.json from bower.json
* Update and/or configure type declarations.

.gitignore

@@ -1,2 +1,3 @@
 bower_components*
 bower-*.json
+node_modules

.travis.yml

@@ -3,6 +3,10 @@ sudo: required
 before_script:
   - npm install -g bower polymer-cli
   - polymer install --variants
+  - >-
+    npm run update-types && git diff --exit-code || (echo -e
+    '\n\033[31mERROR:\033[0m Typings are stale. Please run "npm run
+    update-types".' && false)
 env:
   global:
     - secure: >-
@@ -19,5 +23,7 @@ addons:
       - google-chrome-stable
 script:
   - xvfb-run polymer test
-  - 'if [ "${TRAVIS_PULL_REQUEST}" = "false" ]; then polymer test -s ''default''; fi'
+  - >-
+    if [ "${TRAVIS_PULL_REQUEST}" = "false" ]; then polymer test -s 'default';
+    fi
 dist: trusty

iron-a11y-keys.d.ts

@@ -0,0 +1,31 @@
+/**
+ * DO NOT EDIT
+ *
+ * This file was automatically generated by
+ *   https://github.com/Polymer/gen-typescript-declarations
+ *
+ * To modify these typings, edit the source file(s):
+ *   iron-a11y-keys.html
+ */
+
+/// <reference path="../polymer/types/polymer.d.ts" />
+
+interface IronA11yKeysElement extends Polymer.Element, Polymer.IronA11yKeysBehavior {
+  target: Node|null;
+
+  /**
+   * Space delimited list of keys where each key follows the format:
+   * `[MODIFIER+]*KEY[:EVENT]`.
+   * e.g. `keys="space ctrl+shift+tab enter:keyup"`.
+   * More detail can be found in the "Grammar" section of the documentation
+   */
+  keys: string|null|undefined;
+  attached(): void;
+  _targetChanged(target: any): void;
+  _keysChanged(): void;
+  _fireKeysPressed(event: any): void;
+}
+
+interface HTMLElementTagNameMap {
+  "iron-a11y-keys": IronA11yKeysElement;
+}