computefps: rename 'reduce.latarts' into 'disprel' to make it explicit that this form stems from the lattice dispersion relation and doesn't necessarily reduce the effect of lattice artefacts
computefps: update documentation, taking into account the renaming of 'reduce.lararts' into 'disprel'
Merge pull request #10 from kostrzewa/rename.latarts

computefps: rename 'reduce.latarts' into 'disprel'