kontrol: separate etcd node parsing into a package

This functionality is needed in other places too, no need for code
duplication.
kontrol: expose certain functions and fix race condition
Merge pull request #54 from koding/kontrol-packages

kontrol: expose functions and packages
kontrol: add RegisterURL for more customization during self
registration
Restructure kite/cmd directory for better readability.

All subcommands are in kite/kitectl/command/ directory. Main application
is in kite/kitectl/ directory with the name main.go, like it should be.
Rename 'cmd' package name to 'command'
kitectl: Find the cli package and pass the tests.
kitectl: Use github.com/mitchellh/cli

mitchellh/cli is more tested and more extendable CLI helper. Since
kloudctl is already using it, we can safely use it for kitectl.

Apart from changing the CLI package, I also added help/usage texts and
more error checks.
kitectl: Reflect the changes that are mentioned in the PR.

- Do not stutter by appending `Command` to every subcommand structs.
- Remove version command since the new CLI package already provides this
  functionality.
- Add a default.go file that shares the default objects such as
  Default CLI UI and Default Kite Client.
- Remove population of the commands in main.go. Move this construction into the related subcommands.
- Test kitectl in Makefile.
kitectl: Oops, revert back the ulimit change in Makefile.
Merge pull request #55 from igungor/kitectl

Rename kite binary to kitectl and restructure the kite/cmd directory.
kitectl/query: fix newline, Ui.Output already appends a newline
kontrol: add back a fix, rename RegisterSelf() to InitializeSelf()
kitectl: Open up a prompt when the command is invoked without a username.

Also use a default Kontrol URL (https://discover.koding.com/kite)
kitectl: Fix wrong default Kontrol URL.
kitectl: Do not use a default username.
Merge pull request #57 from igungor/default_registry

kitectl: Open up a prompt when the command is invoked without a username.
kitectl: use discovery.koding.com/kite as default endpoint