CERES: More work on SSL

Read TODOs in NetworkHandler.java
CERES: Input validation for log in page

Made some tweaks to have the log in page progress a little 
smoother. WIP on validation for IP, everything else seems fine.
CERES: Remove debug prints from basic auth

Also fixed an IllegalStateException made for changes to the 
AsyncTask structure in MainActivity to allow cancelable
ProgressDialog (haven't made that change yet).