no code changes, only comments and cleanup.
added a plan/notes file
Partial implementation of synch at command level.

- JobQueue and CommandSequencer from sandbox implementation
session_manager_GUI
- Run Model does not work yet
- scanner.l modified, added ":/" as token synonym of ":\\", but needs to
be perfectioned in parser.y too
- loading a model is very slow now. Maybe this low level synch should
become optional, a kind of debug mode.
CommandSequencer can run in synch mode or not.

Waiting for each lazyNut instruction to be executed before sending the
next makes loading models very slow. Maybe this synch mechanism is not
necessary. For the moment is optional, defaults to no.
High level synchronisation with lazyNut introduced.

- SessionManager substitutes QueryProcessor, added MacroQueue.
- Low level synch is now optional and off y default, the switch value is
represented by the enum class SynchMode
- parser and scanner had the quoted text feature removed, since lazyNut
(still) allows double quote as plain character
- lots of cleanup and testing to be done yet, mainly remove
QueryProcessor entirely.
Added synch mode toggle and pause and stop buttons.

- Pause and stop not refined yet
- cleaned up old classes, NMCmd and QueryProcessor (commented out)
Stop and Pause reviewed, Macro states class hierarchy reviewed.

- Stop does not have a "stopped" state associated anymore
- Only user-generated jobs can be stopped or paused
- JobQueue.freeToRun() now is safe, since mutex is unlocked only if
there's a currentJob.
- A stopped macro will execute its jobs (states) until a user job is
entered, or at the very end if none is encountered.
- New macro states hierarchy: MacroState from QState, GUIState and
UserState from MacroState, QueryState from UserState.
- PAUSE button shows "RESUME" appropriately.