partial work towards embeddeclient
embeddedclient: fixes / merge newer stmclient.cc
embeddedclient: get rid of ioctls, require window size passed in
gitignore emdriver
embeddedclient: Don't initialize the terminal
embeddedclient: Dump row-by-row framebuffer diffs to stdout

Now we are no longer using Terminal::Display, i.e., nothing assumes that
stdout is a terminal.

Obviously debug_contents should go away eventually.
Split embeddedclient into static library
embeddedclient: Move cols/rows from main() to ctor
embeddedclient: Move mainloop out and into emdriver
emdriver: Another sync (e2abb852)
embeddedclient: get rid of vestigial local display for local terminal
Another sync (10ac25f0)
embeddedclient: Expose handle_exception
Another sync (4f68ec3a)
Another sync (4e7e239e)