Merge pull request #25 from elbeardmorez/cmdbuf-focus

fix source buffer erroneously receiving focus
Merge pull request #23 from elbeardmorez/shortkey-hook

Shortkey hook
add customisable variable to control source buffer locking

-allow users to control whether the source buffers associated with
the debugger process(es) are locked (read-only mode enabled) when
debugging is in progress