Remove the stringent pseudodojo sets.

Description

Remove the stringent pseudodojo sets.

These sets have been generated for a specific used, which is to improve the Delta-factor test performances. Unlike the name might suggest, they do not really bring improvement on most TD observables that people might be interested in. Their use should be reserved for expert user, which are aware of their existence, and hence now how and where to find them.

Moreover, these sets represent a large number of files that are included in the tarball and need to be installed every time. Not included them hence makes 'make install' faster and the tarball lighter.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.