Hungarian translation update by mtomi78.

Closes #3934.
Polish translation update by Emdek.

Closes #1347.
Update translations.
Revert "make -Cpo update-po"

This reverts commit 7ac192b384b7542be12eec29bb4c68980f546d40.
Merge branch 'bugfixes' into 3.1

* bugfixes:
  Update translations.
  Polish translation update by Emdek.
  Hungarian translation update by mtomi78.