builder/virtualbox: support generic hash types [GH-175]
builder/vmware: generic checksum types [GH-175]
Update CHANGELOG
builder/common: support sha1/sha256 hashes
command/fix: boilerplate for the fix command
command/fix: fixer for iso_md5 change
command/fix: run the iso-md5 fixer
command/fix: properly replace the escaped </>
Update CHANGELOG for packer fix
website: document the checksum features
website: document the fix command
communicator/ssh: have a Connection func so we can re-establish

[GH-152]
communicator/ssh: ConnectFunc times out after 15 sceonds
communicator/ssh: re-establish ssh connection if possible [GH-152]
fmt
communicator/ssh: retry connection in ConnectFunc forawhile
communicator/ssh: tweakable timeout on retry connection
Update CHANGELOG
communicator/ssh: improved logging
builder/amazonebs: Don't export sshTimeout so it can't be set