Release Name: 1.8.4

gPM 1.8.4
---------

New features:
  o DM 385 : A new serialization tool is now available : the new tool split the export on several and support multi threading
  o DM 433 : Fix problem on import of infine size string fields
  o DM 463 : Performance on link displaying has been improved

Major Bugs fixed :
  o Bug 188 : Sheet import: id have priority on reference
  o Bug 191 : Fix problem on Extention Points TUs with PostGREY database
  o Bug 192 : Fix problem on environment name during import