Features for primary schools

Define a corpus of technical requirements for Dr. Geo to make it user friendly in primary school education.

Dr.Geo should propose:
- a friendly user interface for students and for educators, the requirements may be different depending on the user group
- a good level a feedback
- a good level of customization with script, to ease extended use case of Dr. Geo without the need to modify it.

The methodology is:
1. make a review of geometry activity in primary school,
2. imagine pertinent scenarii for such activities in interactive geometry
3. from these scenarii extract technical requirement for Dr. Geo
4. implement these requirements
5. build the scenarii with Dr. Geo