Decouple window creation from streamers, introduce window ID

Change-Id: Ide36663f620344acb573a7dd9a68476d3cb55095
Merge pull request #76 from tribal-tec/master

Decouple window creation from streamers, introduce window ID
Using boost to serialize the state to xml

Change-Id: I7ddceb82a78abb5f21bd0bd7fcf87db30800ae3d