hot realoading of controller and bug fix

controller is written:

<pre>
@get('/', apply='json', skip='jinja2')
def index():
    return {'word': 'Hello Decanter!'}
</pre>

execute command:

<pre>
./decanter.py -c config/devel.py runserver
</pre>

see this message:

<pre>
{
    word: "Hello Decanter!"
}
</pre>

controller editing:

<pre>
@get('/', apply='json', skip='jinja2')
def index():
    return {'word': 'edited controller!'}
</pre>

Without restarting the server, see this message:

<pre>
{
    word: "edited controller!"
}
</pre>

This is enable only in debug mode.