At state for win_msi and add documentation

library/windows/win_msi

+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# (c) 2014, Matt Martz <matt@sivel.net>, and others
+#
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
+# this is a windows documentation stub.  actual code lives in the .ps1
+# file of the same name
+
+DOCUMENTATION = '''
+---
+module: win_msi
+version_added: "1.7"
+short_description: Installs and uninstalls Windows MSI files
+description:
+    - Installs or uninstalls a Windows MSI file that is already located on the target server
+options:
+    path:
+        description:
+            - File system path to the MSI file to install
+        required: true
+    state:
+        description:
+            - Whether the MSI file should be installed or uninstalled
+        choices:
+            - present
+            - absent
+        default: present
+author: Matt Martz
+'''
+
+EXAMPLES = '''
+# Install an MSI file
+- win_msi: path=C:\\\\7z920-x64.msi
+
+# Uninstall an MSI file
+- win_msi: path=C:\\\\7z920-x64.msi state=absent
+'''
+

library/windows/win_msi.ps1

 #!powershell
+# (c) 2014, Matt Martz <matt@sivel.net>, and others
+#
 # This file is part of Ansible
 #
 # Ansible is free software: you can redistribute it and/or modify
@@ -44,7 +46,14 @@ If ($params.creates.GetType)
 $logfile = [IO.Path]::GetTempFileName();
 $stdoutfile = [IO.Path]::GetTempFileName();
 $stderrfile = [IO.Path]::GetTempFileName();
-msiexec.exe /i $params.path /qb /l $logfile $extra_args;
+if ($params.state.GetType -and $params.state -eq "absent")
+{
+    msiexec.exe /x $params.path /qb /l $logfile $extra_args;
+}
+Else
+{
+    msiexec.exe /i $params.path /qb /l $logfile $extra_args;
+}
 
 Set-Attr $result "changed" $true;