bug fix for gpu simulations with stacey absorbing boundaries; updates gpu kernel headers
updates rules.mk in src/specfem3D to compile adios files without mpif90
added a warning about versions dot zero of a compiler
bug fix for backward/reconstructed wavefield in OpenCL simulations; updates code reformatting
Merge branch 'devel' of https://github.com/geodynamics/specfem3d_globe into devel
bug fix for kernel simulations on OpenCL devices (multiple processes and asynchronuous copy); updates Makefile and rules for OpenCL flags
adds file check_opencl_device.c in utils/ directory for OpenCL device testing
updates configuration script based on newest autoconf functions in m4/
removes trailing spaces