Added a scripting benchmark in test/bench.sh

it accepts four arguments
device=   $1 #cpu or gpu
threads=  $2 # string of number of threads. for example "1 2 8 1024"
infile=   $3 # infile input for example argon_108.inp
benchfile=$4 # where the data gets written to
Merge branch 'master' of https://github.com/LJMD-OpenCL/ljmd-opencl into benchmark
Merge pull request #26 from ajasja/benchmark

Added a scripting benchmark in test/bench.sh