simulator: fix linking against libevent

The Makefile rule for linking the simulator was wrong, append the
libraries last in the linking command line.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
simulator: add missing include for if_nametoindex

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
simulator: add executable to .gitignore

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>