Also changed all "if (this==NULL) return;"s. Fixes some -Wtautological-undefined-compare warnings. Quoting Clang: "'this' pointer cannot be null in well-defined C++ code; comparison may be assumed to always evaluate to false"
.. still, didn't look at unused variable warnings from *.es because so many are generated.
same as before for EntitiesMP/Common/Particles.cpp, this time for the first encounter.
