Added vim-emu install option to installer.

Installer can now (optionally) install and deploy the emulator
at the end of the installation process so that a user
could directly connect OSM to an emulated VIM.

Usage: ./install_osm.sh --lxdimages --vimemu

The emulator is locally build and deployed inside of
a Docker container.

Change-Id: I5f5898fe557fb379506afbca23349f9a193b0711
Signed-off-by: peusterm <manuel.peuster@uni-paderborn.de>