[vsphere] fix broken detection of existing network interface type
Add fence_mode to network model

fence_mode can be 'isolated' (disconnected from EdgeGateway) or
'natRouted' (connected to NatService on EdgeGateway).

The network types differ significantly enough to have a separate
set of tests, to be expanded later.
Ensure get_network_complete mock returns like API

Booleans were being passed through unaltered. The API
returns them as strings, and in Real mode we do not post-process
them into boolean types.

Update so that booleans are returned as strings, as per
Real mode.
Add is_shared attribute to network Model

is_shared reports whether a network is shared across all
vDCs within an organization, or just within the vDC it is defined in.
Update to attempt to alleviate confusion between Directory.new and get.

May want to have Directory metadata load only on #each instead of #get
Removing superfluous markup
Incorporated feedback from @mikhailov
[aws/security_group] update mock search and revoke

* update #normalized_permissions to work with GroupId
* fix #describe_security_groups ip-permission.group* filters
Merge pull request #2715 from fog/rackspace_storage_docs

Update to attempt to alleviate confusion between Directory.new and get.
[GH-2630] Bring in Minitest

This adds Minitest as a dependency and replaces the old `rake test`
by a Rake test runner.

Travis now includes the Minitest run before the Shindo run
[aws/compute] delete_security_group mock fixes

* mock delete failures when instances are present
* fix mock describe_instances by group-id
Merge pull request #2717 from fog/add_minitest

[GH-2630] Bring in Minitest
Merge pull request #2716 from engineyard/firewall-in-use

[aws/security_group] update mock search and revoke
Merge pull request #2664 from mmatuska/vsphere_fix_nic_detection

[vsphere] fix broken detection of existing network interface type
Merge pull request #2712 from alphagov/vcd_network_model_extras

[vcloud_director] network model fence_mode and ip_shared attributes