Merge branch 'v2.3' into v2.4

CHANGES/v2.3.md

@@ -201,7 +201,7 @@ For developers:
   find them without explicitly setting `DYLD_LIBRARY_PATH`. This should also make the `DYLD_LIBRARY_PATH` irrelevant.
   Notice that `DYLD_LIBRARY_PATH` is not well behaved in OSX El Capitan.
 
-## Version 2.3.4 (coming soon)
+## Version 2.3.4 (Dec 15, 2017)
 
 For users:
 - GROMACS patch updated to gromacs-2016.4. This patch was also fixed in order to properly work with \ref ENERGY (see \issue{316})