PuppetBoard: Upgrading WTForms to latest version and restoring CSRF Protection (#250)

Upgrading the following packages to the respected versions:

WTForms==2.1
Flask-WTF==0.12
Werkzeug==0.11.0

Passing newly required metadata to the QueryForm constructor in puppetboard/app.py

Apache >= 2.4 with mod_wsgi experienced a major issue where it would re-generate
the app's secret key on each request. The fix for this turned out to be placing
a permanent statis 'secret_key' value in the wsgi.py. Adding a block in README.rst
on how to implement the user's own secret_key

setup.py

@@ -30,8 +30,8 @@ setup(
     long_description='\n'.join((README, CHANGELOG)),
     install_requires=[
         "Flask >= 0.10.1",
-        "Flask-WTF >= 0.9.4, <= 0.9.5",
-        "WTForms < 2.0",
+        "Flask-WTF >= 0.12, <= 0.13",
+        "WTForms < 3.0",
         "pypuppetdb >= 0.3.0, < 0.4.0",
         ],
     keywords="puppet puppetdb puppetboard",