Add netmap feature
Update INSTALL doc
Merge branch 'master' into Feature_netmap
Add messages explaining when switching to network bypass and when switching back to normal
update netmap install instructions
Merge branch 'master' into Feature_netmap
netmap is no longer the default injector, rather it is enabled via the --netmap option
change netmap description slightly
Merge branch 'master' into Feature_netmap

Repaired conflicts:
	src/tcpreplay_api.c
Merge branch 'Feature_netmap' into 4.0