Future:
    
    - Strings view.
    - Field parsing and editing.
    - On-the-fly generation of keys, signed with a CA
    - Pass-through fast-track for things that don't match filter?
    - Reading contents from file
    - Shortcut for viewing in pager
    - Serializing and de-serializing requests and responses.
    - Use real non-blocking input handling to minimize cpu load.
    - Upstream proxies.
    - mitmdump
        - Filters
        - Sticky cookies
        - Pipe to script
        - After we add serialization of flows, command-line replay

Bugs:
    
    - In some circumstances, long URLs in list view are line-broken oddly.
    - Termination sometimes hangs.