Remove unsupported (DLL) builds from solution.
Rename msvc bitcoin-client to example-client
Move the obelisk stuff into its own folder
Remove obelisk_router::set_message_stream

Changing this in mid-communication would break the state machine.
If a client wants to change streams,
they should just create a new obelisk_codec instance.
Split the obelisk codec into two parts

One part handles the request/reply matching,
and the other handles the individual message encoding.
Remove enable_sideeffects from sleeper interface
Fix API data widths