Adding support for Chapel v1.6.0

Signed-off-by: Fotis Georgatos <fotis.georgatos@uni.lu>
added geant4 easyblock
added geant4 and root with v1.0 compatibility
Support for binary GHC packages
Remarks by boegel.
Added import for LooseVersion
fixed remarks
implemented easyblock for NEURON, still WIP because run_test needs to be fixed
NWChem easyblock, ready to start testing (but incomplete w.r.t. module file generated and testing)
set LIBMPI correctly depending on MPI library being used, make sure LIBS is not defined when building
drop guard on usempi
symlink build dir to short path, i.e. random subdir in /tmp to get around 64-char limit on build path name (yes, there's a technical reason for it, see -DBASIS_LIBRARY preprocessor value when compiling bas_input.F
fix install step
fix typo
set proper default for MSG_COMMS
fix install step, shutil.copytree doesn't like it if destination already exists
track setting of environment variables
correct overly aggressive refactoring in install step, create default NWChem setting file
fix use of self.moduleGenerator
set correct NWCHEM_BASIS_LIBRARY