Autoname option

[hilaire]

An auto-naming option will be handy for scenario like:

- auto-name option on [X]
- create a segment, it is named [AB]
- ask the length of segment [AB], this value is named AB

[Vic Pet (vic555)]

I noticed points and other objects don't get any name automatically, and I find that important too (ex, when following some instructions on building some constructions).

[hilaire (hilaire-fernandes)]

I could add a preference to have auto-name of point.

[hilaire (hilaire-fernandes)]

Implement a first iteration of autoname for point only.
By default unactivated, user should go to Preferences>Miscellanous.
Likely to break in some places unknown yet...
To be tested