Kurtis Rader bd299e96b2 implement status is-breakpoint
This implements `status is-breakpoint` that returns true if the current
shell prompt is displayed in the context of a `breakpoint` command.

This also fixes several bugs. Most notably making `breakpoint` a no-op if
the shell isn't interactive. Also, typing `breakpoint` at an interactive
prompt should be an error rather than creating a new nested debugging
context.

Partial fix for #1310
2017-06-20 17:18:59 -07:00
..
2017-06-16 21:01:57 -07:00