use DEFAULT_FFTW_FLAG instead of FFTW_MEASURE

See merge request !20

NSVE (and implicitly NSVEparticles) was using FFTW_MEASURE when creating
the `vorticity_equation` object.

Feature/sampling new particles test (extension of Update particles sampling for variable dim)

See merge request !19

switching to other computer

Berenger Bramas authored May 19, 2017 and Cristian Lalescu committed May 23, 2017

Add a sampling method -- update to be generic against the field -- need to update NSVEparticles::do_stats

Feature/extend ci

See merge request !18

Feature/gitlab ci

See merge request !17

Add a lagrange file wrapper for the particles system

See merge request !16