Added PasswordInput widget similar to TextInput (#655)

examples/reference/widgets/PasswordInput.ipynb

@@ -0,0 +1,102 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import panel as pn\n",
+    "pn.extension()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from panel.widgets.input import PasswordInput"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The ``PasswordInput`` allows entering any string using a obfuscated text input box.\n",
+    "\n",
+    "For more information about listening to widget events and laying out widgets refer to the [widgets user guide](../../user_guide/Widgets.ipynb). Alternatively you can learn how to build GUIs by declaring parameters independently of any specific widgets in the [param user guide](../../user_guide/Param.ipynb). To express interactivity entirely using Javascript without the need for a Python server take a look at the [links user guide](../../user_guide/Param.ipynb).\n",
+    "\n",
+    "#### Parameters:\n",
+    "\n",
+    "For layout and styling related parameters see the [customization user guide](../../user_guide/Customization.ipynb).\n",
+    "\n",
+    "##### Core\n",
+    "\n",
+    "* **``value``** (str): Any string\n",
+    "\n",
+    "##### Display\n",
+    "\n",
+    "* **``disabled``** (boolean): Whether the widget is editable\n",
+    "* **``name``** (str): The title of the widget\n",
+    "* **``placeholder``** (str): A placeholder string displayed when no value is entered\n",
+    "\n",
+    "___"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "password_input = pn.widgets.input.PasswordInput(name='Password Input', placeholder='Enter a string here...')\n",
+    "password_input"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "``PasswordInput.value`` returns a string type that can be read out and set like other widgets:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "password_input.value"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3 [anaconda50_py36]",
+   "language": "python",
+   "name": "anaconda-project-anaconda50_py36-python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}

panel/widgets/input.py

@@ -15,7 +15,8 @@
 from bokeh.models.widgets import (
     CheckboxGroup as _BkCheckboxGroup, ColorPicker as _BkColorPicker,
     DatePicker as _BkDatePicker, Div as _BkDiv, TextInput as _BkTextInput,
-    Spinner as _BkSpinner, FileInput as _BkFileInput)
+    PasswordInput as _BkPasswordInput, Spinner as _BkSpinner, 
+    FileInput as _BkFileInput)
 
 from ..util import as_unicode
 from .base import Widget
@@ -29,6 +30,13 @@ class TextInput(Widget):
 
     _widget_type = _BkTextInput
 
+class PasswordInput(Widget):
+
+    value = param.String(default='', allow_None=True)
+
+    placeholder = param.String(default='')
+
+    _widget_type = _BkPasswordInput
 
 class FileInput(Widget):