When the vars, locals, or args commands return no results, nothing is
printed out to the terminal. This commit makes these commands print a
message like `(no locals)` when there is nothing to show. This feedback
is more descriptive of what is being returned than an empty string.
Implements extensible mechanism to specify which commands accept
prefixes (goroutine, frame, on) instead of hardcoding them in
a switch.
Implements #240
The 'source' command reads the file specified as argument and executes
it as a list of delve commands.
Additionally a flag '--init' can be passed to delve specifying a file
containing a list of commands to execute on startup.
Issue #96
Refactor to introduce client/server separation, including a typed
client API and a HTTP REST server implementation.
Refactor the terminal to be an API consumer.
