import multi-element compatible pair style edip as edip/multi

doc/src/Section_commands.txt

doc/src/pair_edip.txt

examples/USER/misc/edip/Si.edip

examples/USER/misc/edip/SiC.edip

examples/USER/misc/edip/data.SiC

examples/USER/misc/edip/in.edip-Si

examples/USER/misc/edip/in.edip-Si-multi

examples/USER/misc/edip/in.edip-SiC

examples/USER/misc/edip/log.4May2017.g++.edip-Si-multi.1

examples/USER/misc/edip/log.4May2017.g++.edip-Si-multi.4

examples/USER/misc/edip/log.4May2017.g++.edip-Si.1

examples/USER/misc/edip/log.4May2017.g++.edip-Si.4

examples/USER/misc/edip/log.4May2017.g++.edip-SiC.1

examples/USER/misc/edip/log.4May2017.g++.edip-SiC.4

src/.gitignore

src/USER-MISC/pair_edip.cpp

src/USER-MISC/pair_edip_multi.cpp

src/USER-MISC/pair_edip_multi.h