Fix multiple bugs related to GPC parameters pollution from code

Was introduced by me in e1a5b9c54f3ea112a0ce5b2f0f3a0ace9583a354 while
trying to make parameter more plugin friendly. display.php code default
code use a defined set of GPC parameter and make them persitent between
two call (while paging or sorting data). Any other parameter is ignored
and doesn't survive a new call. This patch attempted to make plugin
specific GPC parameters persistants, but was making ALL parameters
persitants, introducing a bunch of bug.

This one revert part of this previous patch but keep the small
house-cleaning.