Move sap_soap_rfc_sxpg_command_exec to multi dir
Clean up and multi platform support for sap_soap_rfc_sxpg_command_exec
Merge pull request #10 from jvazquez-r7/sap_soap_rfc_sxpg_command_exec_multi

sap_soap_rfc_sxpg_command_exec multi platform and clean up