Simplify the way we annotate observable properties

We no longer add observable annotations to the constructor.
Instead, we just mark getters (and for read/write properties
also setters) with an observable annotation.

src/ol/dom/input.js

@@ -29,8 +29,6 @@ ol.dom.InputProperty = {
  * @constructor
  * @extends {ol.Object}
  * @param {Element} target Target element.
- * @todo observable value {string} the value of the Input
- * @todo observable checked {boolean} the checked state of the Input
  * @todo api
  */
 ol.dom.Input = function(target) {
@@ -58,7 +56,8 @@ goog.inherits(ol.dom.Input, ol.Object);
 
 /**
  * If the input is a checkbox, return whether or not the checbox is checked.
- * @return {boolean|undefined} checked.
+ * @return {boolean|undefined} The checked state of the Input.
+ * @todo observable
  * @todo api
  */
 ol.dom.Input.prototype.getChecked = function() {
@@ -72,7 +71,8 @@ goog.exportProperty(
 
 /**
  * Get the value of the input.
- * @return {string|undefined} input value.
+ * @return {string|undefined} The value of the Input.
+ * @todo observable
  * @todo api
  */
 ol.dom.Input.prototype.getValue = function() {
@@ -86,7 +86,8 @@ goog.exportProperty(
 
 /**
  * Sets the value of the input.
- * @param {string} value Value.
+ * @param {string} value The value of the Input.
+ * @todo observable
  * @todo api
  */
 ol.dom.Input.prototype.setValue = function(value) {
@@ -100,7 +101,8 @@ goog.exportProperty(
 
 /**
  * Set whether or not a checkbox is checked.
- * @param {boolean} checked Checked.
+ * @param {boolean} checked The checked state of the Input.
+ * @todo observable
  * @todo api
  */
 ol.dom.Input.prototype.setChecked = function(checked) {