- Only use JSON_FORCE_OBJECT when parameters are empty (fixes issue where adding labels to issues fails).
Add Class for releases.
Docs & a comment
Merge pull request #48 from InventisPMTest/master

Fix "Body should be a JSON Array" issue
Update CS
make it possible to list all labels and create them

Allow the following syntax to work, from doc/issue/labels.md
```php
$labels = $client->api('issue')->labels()->all('KnpLabs', 'php-github-api');
```

Also add an interface for creating labels.
Merge pull request #75 from AD7six/feature/create-labels

Implement listing all labels, and creating labels
provide a better missing error message

When github say's missing, it's not talking about the resource - it
means something referenced in the data.

For example, specifying a milestone that doesn't exist will return:

```
{
	"message": "Validation Failed"
	"documentation_url": "http"://developer.github.com/v3"
	"errors": [
		{
			"value": 42,
			"resource": "Issue",
			"field": "milestone",
			"code": "missing"
		}
	]
}
```

Previously this would be reported as:

> Validation Failed: Resource "Issue" not exists anymore

Now it's reported as

> The milestone 42 doesa not exist, for resource "Issue"
Red test
Green test
Replace other urlencode with rawurlencode
Merge pull request #78 from KnpLabs/feature/rawurlencodefix

rawurlencode instead of urlencode, fixes #77
Merge pull request #76 from AD7six/feature/better-missing-error

provide a better missing error message
Merge remote-tracking branch '1/releases-class' into feature/gh-api-release
Update README.markdown
Add tests, add more release apis, add assets api, update docs
Add manifold preview media type
Merge pull request #79 from KnpLabs/feature/releases-assets

Releases and assets
Migrate from Buzz to Guzzle
Fix CachedHttpKernel tests, fix events