Following work on reorganising the requires, there was an inconsistent
approach to where service wrappers are required. (Fog::Compute...)
Since they should be standardised and shared across providers (although
they really aren't yet) they have been moved to `fog-core` gem.
Each provider has their own `lib/fog/{provider}/core` files that is
required by each of their services. These files should all require
`fog/core` which already required most or these.
So this removes the extra cases to concentrate them in core.
This patch has several purposes. Firstly this patch brings the
Fog vmfusion provider in line with the recently released v0.4.0 version
of the Fission project by aligning various method names. During this
sync up servers.rb was modified to obtain all VM states and passing
them to the raw object instead of doing so when attributes are
obtained inside server.rb. This improves performance a lot since it
reduces the need to run vmrun for every VM on the system. Other
changes being made to the provider are so that it returns data and acts more
similar to the vsphere provider while still keeping backward
compatibility with the original implementation; which was to be more
similar to various cloud providers.
