Fix flask deprecation warnings

[johnnykv]

Some of them:

/Users/jkv/repos/beeswarm/beeswarm/server/webapp/app.py:142: FlaskWTFDeprecationWarning: "flask_wtf.Form" has been renamed to "FlaskForm" and will be removed in 1.0.
  form = LoginForm()
ok
Tests if all sessions are returned properly ... /Users/jkv/repos/beeswarm/beeswarm/server/webapp/app.py:142: FlaskWTFDeprecationWarning: "flask_wtf.Form" has been renamed to "FlaskForm" and will be removed in 1.0.
  form = LoginForm()
/Users/jkv/repos/beeswarm/beeswarm/server/webapp/app.py:142: FlaskWTFDeprecationWarning: "flask_wtf.Form" has been renamed to "FlaskForm" and will be removed in 1.0.
  form = LoginForm()
ok
Tests if attacks are returned properly ... /Users/jkv/repos/beeswarm/beeswarm/server/webapp/app.py:142: FlaskWTFDeprecationWarning: "flask_wtf.Form" has been renamed to "FlaskForm" and will be removed in 1.0.
  form = LoginForm()
/Users/jkv/repos/beeswarm/beeswarm/server/webapp/app.py:142: FlaskWTFDeprecationWarning: "flask_wtf.Form" has been renamed to "FlaskForm" and will be removed in 1.0.
  form = LoginForm()

[gnomefish]

I'm getting these when starting the server, it works but seems like some things need to be fixed :)

2017-01-30 17:22:06,044 (root) Cleaned 0 pending sessions on startup
/usr/local/lib/python2.7/dist-packages/gevent/builtins.py:93: ExtDeprecationWarning: Importing flask.ext.login is deprecated, use flask_login instead.
result = _import(*args, **kwargs)
/usr/local/lib/python2.7/dist-packages/gevent/builtins.py:93: ExtDeprecationWarning: Importing flask.ext.wtf is deprecated, use flask_wtf instead.
result = _import(*args, **kwargs)