Version 2

## Changes
Completely removed dependency on [shenzhen](https://github.com/nomad/shenzhen), and I'm instead now using the built-in `xcodebuild`.

Please check out the online [man page for `xcodebuild`](https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/xcodebuild.1.html) or simply run `$ man xcodebuild`.


## todo
- [x] Update `README.md`
- [ ] Add examples to `README.md`
- [x] Show `stdout` when `--verbose`
- [x] Plugin options
  - [x] `clean` option
  - [x] `export` option
  - [x] `project` option
  - [x] `configuration` option
  - [x] `workspace` option
  - [x] `scheme` option
  - [x] `allTargets` option
  - [x] `target` option
  - [x] `archivePath` option
  - [x] exporting
    - [x] `exportFormat` option
    - [x] `exportPath` option
    - [x] `exportFilename` option
    - [x] `exportProvisioningProfile` option
    - [x] `exportSigningIdentity` option
    - [x] `exportInstallerIdentity` option
  - [x] `arch` option
  - [x] `sdk` option
- [ ] Unit tests

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Would love some feedback on the code so far, and what you guys want to see in the project.