This is better design because the cursor and eventhandler are things the
buffer should know about directly but the view shouldn't. This should
make it easier to add persistent undo or location saving between
sessions (see #107).
It seems rope.Report is not acting how I expected it to. I need to look
into this in more detail but for now I am adding the Text variable back
to the Buffer.
Fixes#98
This commit splits "Boss mode" into to different actions. Executing
a command with Ctrl-b will now open an interactive terminal. If you
would simply like to execute a background job in the shell, press
Ctrl-e and then type `run shell-command`.
