Don't upload guest additions/vmare tools manually

Let packer handle it and upload into /tmp
Use 2 CPUs and 512MB RAM
export as vagrant box
Add veewee converted ubuntu-12.04.2-server-amd64-packages
fix test for vmware installation
Add shebang to run installer for VBox-additions and VM-tools in bash
Add some more essential dev packages
split postinstall.sh into single scripts

using existing common scripts
exec all scripts with bash

not simple sh or ubuntu-default dash
fix checksums for iso download
add vagrant postprocesor