Merge pull request #146 from dougm/device-helpers

Add floppy related device helpers and commands
Add serial port device related helpers
Add device.serial cli commands
Merge pull request #147 from dougm/serial-device-helpers

Add serial port related device helpers and commands
Add test cleanup script

Cleanup any VMs or .{vmdk,iso,img} artifacts created by govc
32M is plenty of memory for ttylinux
boot order test fixups

- decrease boot delay

- reorder cleanup commands
Change vm.ip -esxcli to wait for ip

Similar to vm.ip (tools), the -esxcli option waits until the VM has a
valid ip address.  Unlike the tools option, -esxcli needs to poll.
Collapse whitespace in assert_line helper

This helper is often used against Go's tabwriter output,
where number of spaces may vary.
Explicit exit status check in assert_failure

Check that exit status is 1.  A go panic for example would result in
an exit status of 2.  We should never panic.
Include esxcli method info in response

The Hints include info about the esxcli method output, such as formatter
type (table, simple), human readable field names and units.
Add table formatter to esxcli command
Merge pull request #148 from dougm/esxcli

Add table formatter to esxcli command
Cache esxcli command info

Reduces calls to hostd when we are polling for vm.ip -esxcli for
example.
Merge pull request #149 from dougm/esxcli

Cache esxcli command info
Add DistributedVirtualPortgroup constructor
Fix collapse_ws helper
Add vcsim_env helper

Tests can use this helper to optionally run against vcsim.
Add NetworkReference interface

This interface currently has 1 method to get the
VirtualDeviceBackingInfo, implemented by the Network and
DistributedVirtualPortgroup types.
Add network bats test