builder/vmware: new driver to support building images directly on ESX

This driver talks directly to ESX over ssh, using vim-cmd, esxcli and sh;
no vCenter or VIM api required.

Remote* config properties added to support a remote driver

RemoteDriver interface extends Driver:
* SSHAddress - esx flavor uses esxcli to find the VM's ip address
* Download - esx flavor downloads iso files to a vmfs datastore

Driver can optionally implement the following interfaces:
* VNCAddressFinder - esx flavor needs to check remote ports
* OutputDir - esx driver needs a local and remote OutputDir
* Inventory - esx driver needs to register/unregister VMs
* HostIPFinder - esx flavor needs an address on the same network as esx itself
builder/vmware: make things more Go-like

This commit currently breaks the builder though, since the ISo is now
uploaded back into ESX.
Update CHANGELOG
builder/vmware: upload the ISO to the ESXi machine
website: vmware esxi docs
website: esxi docs
Fix spelling in Use Cases documentation
builder/vmware: esx file check works properly
builder/vmware: make upload dst,src like normal go
builder/vmware: set proper default disk type for esx
builder/vmware: for remote builds, put VMX in temp dir
builder/vmware: log when writing a VMX
builder/vmware: register the VMX to the proper path on esx
builder/vmware: only unregister if registration success
builder/vmware: start/stop ESXi5 VMX with proper path
Merge pull request #607 from fgo/patch-1

website: Fix spelling in Use Cases documentation [ci skip]
Fix spelling in Provision documentation [ci skip]
builder/vmware: case-insensitive VMX creation [GH-608]
Merge pull request #609 from fgo/patch-2

website: Fix spelling in Provision documentation [ci skip]
builder/amazon/chroot: quote commands and pass through a shell [GH-581]