Fixed error in gyration manual

(cherry picked from commit 650bc4f0c5b69ee7054cea263f7cd9edd50ef924)
WHOLEMOL: fix example

(cherry picked from commit 30ff9e3cf4fc2f60b846e6dc4e78182885e6fb3b)

Conflicts:
	src/generic/WholeMolecules.cpp
Removed timestamp from manual

This will allow me to simplify the update of online manual
(before I needed to remove with a scripts the timestamps
a posteriori to avoid too many differences at every update)
changed pointer to github log
Merge branch 'v2.0' into v2.0-hrex