Monkey patch `knife bootstrap` to support knife-solo

Add `--solo` command line option and `knife[:solo]` configuration
parameter to `Knife::Bootstrap` that can be used for triggering
`Knife::SoloBootstrap` instead of the normal template based chef-client
bootstrap.

This is especially useful with other knife plugins like knife-ec2 that
invoke `knife bootstrap` after creating an server instance. Even if
these plugins do not have the `--solo` option, you can put
`knife[:solo] = true` in knife.rb.
Add integration test for `knife bootstrap --solo`

Convert Debian 7 test for this.
Document knife bootstrap integration
Merge branch 'master' into knife-bootstrap-solo
Use `config_value` helper for `:solo`
Rename original `run` alias to `run_with_chef_client`

More informative than `orig_run`.
Extract knife-solo bootstrapping to own method
Merge pull request #207 from tmatilai/knife-bootstrap-solo

Integrate knife-solo to `knife bootstrap`

Monkey patch Knife::Bootstrap to include `--solo` option (and `knife[:solo]` configuration options) to trigger `knife solo bootstrap` instead of the normal template based bootstrap.