Add TypeScript declarations to paper-input. (#629)

* Tighten keyBindings type.
* Generate minimal package.json from bower.json
* Update and/or configure type declarations.
* Tighten some types from review comments.

.gitignore

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

.travis.yml

@@ -3,6 +3,10 @@ sudo: required
 before_script:
   - npm install -g 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: >-

all-imports.d.ts

@@ -0,0 +1,13 @@
+/**
+ * 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):
+ *   all-imports.html
+ */
+
+/// <reference path="paper-input.d.ts" />
+/// <reference path="paper-textarea.d.ts" />
+