loosening iso matching to allow the version number

Fixes issue: https://github.com/dotless-de/vagrant-vbguest/issues/48
proper regex escape the '.' in a filename

don't open a regex group for the guest version in a filename
Allow multiple places on host system to be searched for iso file
Add additional check for windows environment variables when searching iso file
Note recent updates in changelog
Back-port: reworked usage of vagrant internals

UI interface moved from `vm` to `env`
fix typo
reworked usages of vagrant environent

in all internal classes, pass the `vm` instead of action or command `env` and use the vm's environment for all other purposes.
reworked usage of vagrant internals

in vagrant 1.1 the UI interface moved from `vm` to `env`, `vm.driver` is now `vm.provider`, `vm.channel` is now `vm.communicate` and good old VirtualBox `vm.uuid` is now more general `vm.id`
quick fix command

- remove old tests on VM state
- correct call to vbguest internals (passing vm not env)
- correct cal to UI
vagrant 1.1 style plugin loading

inspired by AWS plugin, raise an error, when not running in a vagrant environment
no longer use ruby 1.8 backwards compatibility Strings, since vagrant 1.1 depends on ruby 1.9
merge vagrant 1.0 compats