CIMI Systems: fix for DTACLOUD-559 - id was not set for SystemMachineCollection and SystemVolumeCollection

https://issues.apache.org/jira/browse/DTACLOUD-559
https://github.com/deltacloud/deltacloud-core/pull/28
https://github.com/deltacloud/deltacloud-core/pull/27
Tests: hard-code minitest < 5.0.0 until 5.0.0 compatibility issues can be looked at in detail
FGCP: read FGCP_CERT_DIR env var in method instead of start of class
to allow unit tests to set it.
The old way stopped working because drivers are now preloaded at startup.
Tests: skip tests on Windows that rely on fork() as it is not supported
Tests: fix minor typos in readme.
Tests: add 'network_interfaces' to expected attributes in instances
Tests: correct number of instances owned by 'mockuser'
(inst3's owner is mockuser base64 encoded)
UI: don't expose actions that the driver does not support
for network related resources
FGCP: Network API rev 3 - FGCP Driver implementation
CIMI: added CIMI::Model constant to fix DTACLOUD-560
Core: Refactor how we load dependencies

This patch follow the discussion on mailing list
about the need of consolidate how we load our dependencies
in Deltacloud API.

This patch will remove *all* `require` from Deltacloud code
(except drivers) and require *all* dependencies on one place:

'dependencies_initializer.rb'.

Depending on how you use Deltacloud API, it will use Bundler or
fallback to system gems.
Core: Removed OrderedHash core_ext (obsoleted in MRI1.9)
Core: Added 'generate:gemspec' rake task

The 'gemspec' is not longer loaded in Gemfile.
For this we need to update deltacloud-core.gemspec
everytime we do a release (or doing `gem build`).
Core: Fixed dependencies for deltacloud-db-upgrade
CIMI: map cimi networks and forwarding groups to Deltacloud
subnets and networks
CIMI: expose import and export of systems and system templates
for drivers that support these operations
CIMI client: fix typo fcgp->fgcp
CIMI Systems: fixed id not being set for SystemSystemCollection.
This was missed in the patch for DTACLOUD-559
(commit 640405627827bdf0d38e3418647d2d36fd272d74)
Also, applied name change of add_/remove_ methods to collections.

    https://issues.apache.org/jira/browse/DTACLOUD-559
    https://github.com/deltacloud/deltacloud-core/pull/28
    https://github.com/deltacloud/deltacloud-core/pull/27
Client: Lock the 'minitest' gem version to '<5.0' because of bug in turn.
Fix failing travis builds - also DTACLOUD-562

https://travis-ci.org/deltacloud/deltacloud-core/builds/7731674
https://travis-ci.org/deltacloud/deltacloud-core/jobs/7763133
https://issues.apache.org/jira/browse/DTACLOUD-562