GUI with cherrypy and bootstrap

I changed the following GUI https://github.com/JahPowerBit/BoottleXCP to use CherryPy instead of Bottle and it is fully integrated in counterpartyd.
I tried to respect the style of code. 

Here are the new arguments of counterpartyd:

* --activate-gui : run GUI web server
* --gui-host : the host to provide the counterpartyd GUI
* --gui-port : port on which to provide the counterpartyd GUI
* --gui-user : required username to use the counterpartyd GUI (via HTTP basic auth)
* --gui-password : required password (for gui-user) to use the counterpartyd GUI (via HTTP basic auth)

And the corresponding keys in config file:

* gui-host
* gui-port
* gui-user
* gui-password 

Default values are:

* gui-host = rpc-host
* gui-port = 8080
* gui-user = rpc-user
* gui-password = rpc-password

Thank you in advance for your time to check this code.