Adds basevmdk config directive

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)
updates cmdInit() to check for B2D.VMDK

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)
Adds helper to copy a specified disk image for the persistent partition

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)
Updates util/cmd() to re-assign STDIN/STDOUT/STDERR when using SSH

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)
Updates in-line deferred function to not return

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)
Adds named return value to copyDiskImage()

Docker-DCO-1.1-Signed-off-by: Isaac Boehman <admin@yacn.pw> (github: yacn)
Print error from config()
Ignore empty lines in config file
Fixed sample config file

We do not curretly support trailing comments yet, so all comment lines
must be on their own.
Prettier config sample with syntax hilighted codeblock
Merge pull request #78 from yacn/fix/broken-cmdSSH

Fixes util.go/cmd() so cmdSSH() works again
use backup files for iso's and delete before rename to help windows get along
update version, I want to do a release
Merge pull request #82 from riobard/fix/config

Fix/config
Merge pull request #86 from SvenDowideit/iso.bak

use backup files for iso's and delete before rename to help windows get along
Merge pull request #79 from yacn/feature/basevmdk

Adds config option to specify a base disk image for persistence partition
Ran `gofmt`
Merge pull request #87 from riobard/gofmt

Ran `gofmt`