- maps now use a linearized 2D array of char until
  entities as structures appear
- structures entities are now pointers by default,
  to keep the API consistent and not change all
  `entity` by `entity*`

for the first high-level section.
Added options --list and --all to make_engine to respectively only list
versions and generate all versions, including the ones in subsequent high-level
sections (versions that are WIP)

Unit test where a map is loaded from a string and updated.

See merge request !73

When launching a level, do not do a "reload" but a regular, load.

See merge request !72

Separated the  compile_reload_level into compile_level + reloading.
Moved the main level loop into its own method for greater readability/maintenability.

'start' in console will make the view change back to game if not already the current view.

See merge request !71

to the level, instead of sending None.
Interrupting in the window raises a KeyboardInterrupt, caught in the main prog to exit
gracefully, showing information on running threads of log.info level.

Refactoring of the whole loading level part.

See merge request !69

(TrackerHelp object).

message in prompts.

Loading characters from map

See merge request !67

Feature: can now provide only a substring for the --level command-line argument

See merge request !66

Progress manager optimization

See merge request !65

Restart don't work without this

See merge request !63

PET_FOLLOW : Level is playable and they are bug inside

See merge request !39

(in particular, it can delete temporary directories/files)