Support WinRM communicator, offline builds, more

* Update to work with WinRM communicator
  (https://github.com/mitchellh/packer/pull/1175)
* Support offline builds by searching for files locally, before
  attempting to download them
* Strengthen error checking/reporting
* Add `floppy/unzip.vbs` to remove 7zip requirement
* Add `lessmsi` to avoid *installing* 7zip to extract files from iso
* Prepare for https://github.com/mitchellh/packer/issues/1181
* Move most cleanup/delete code to `clean.bat` to aid debugging
* Download VMWare Tools ISO, if not available locally
* Download Virtualbox Guest Additions ISO, if not available locally
* Add `CYGWIN_MIRROR_URL` to `_packer_config.cmd`. Fixes #12
* Add 5 other useful variables to `_packer_config.cmd`
* Add `_packer_config_local.cmd` (similar to `Makefile.local`)
* Allow many script variables to be overriden in `_packer_config*.cmd`
* Standardize scripts to use same logic, and case, throughout

* Wait until ssh service is stopped before opening port 22
* Wait until winrm service is stopped before opening port 5985
* Wait until installation is done before starting winrm service
* Replace `timeout` with `choice`, as `timeout` sees mouse click as
  keypress in `00-run-all-scripts.cmd`
* Fix `_download.cmd` to work if filename differs from URL
* Uppercase environment variable names in `.ssh/environment` to be
  consistent with Cygwin standard
* Replace `%TEMP%` with `%SystemRoot%\Temp` in `openssh.bat`
fix sdelete fail due to start prefix
fix when cm=nocm, cm_version is not defined
Improve debugging logic, minor bug fixes, etc.

Log floppy script output via `tee.js`
Include floppy script output in packer log via `dump-logs.cmd`
Beep on error
Standardize ssh password as D@rj33l1ng due to password requirements
Fix `sshd_server` username
Don't abort if shared folders are not available
Fix `pushd` in `script/vmtool.bat`
Fix small typo in `floppy/zz-start-sshd.cmd`
Undid sshd_server username fix as it just masks the issue
Add `ping` at end of scripts to force script output
Fix test-box failure by adding "config.vm.guest = :windows" to tpl files

Remove chkdsk from zzz-debug-log.cmd as it hangs on occasion
Change fatal to warning in save-temp-dirs.cmd
Bumping version of openssh
Reverting back to previous version - VMware tools don't install on Win 8.1/8
Merge branch 'support-winrm-better-error-handling-etc-v2'
Install vagrant-serverspec only if it is not already present
Newer versions of chef client start with chef-windows
Also added simply chedk option
Update README.md
Updating build machine Makefile
Fixing typo in build machine Makefile
Switching to CDN, no need to upload multiple times
Adding versioning to box files