This makes some other changes:
* Moves packer related files to packer directory.
* Updates build scripts for new packer directory.
* Renames boxes to metasploitabl3-<OS>
Only use one packer build file with both virtualbox and vmware defined.
Having multiple build files will make it difficult to keep things consistent.
Also update references in the build scripts to only build for virtualbox
by default.
this is in response to issue #78 "build_win2008.ps1 Failing version check"
exactMatch sends the string "--exactMatch" to the CompareVersions function instead of $False
