some a little changes add new integrator little changes in helper class
Merge branch 'master' of https://github.com/openworm/Smoothed-Particle-Hydrodynamics
1) Fix some warnings 
2) Add license agreement in every file 
3) Put elasticity coefficient to owPhysicsConstant.h file
4) Worked with owHelper class
change integrator method in positionpredition kernel
little changes with precompiler derectives in owHelper.h
cut some comment
delete ofset varialble from pcisph_computeElasticForces kernel
Sync with geppetto change default configuration on elastic cube with membranes and water inside. For loading worm body configuration change generateWormBodyConfiguration on 1.