App dependencies php version

First app dependencies just arrived: minimum and maximum php versions and supported databases:

```xml
	<dependencies>
		<php>
			<min-version>5.4</min-version>
			<max-version>5.4</max-version>
		</php>
		<database>sqlite</database>
		<database>mysql</database>
	</dependencies>

Although this is private it is probably better to not rely on state and make these methods side effect free like:

```php
return array_merge($this->analyizePHPVersion(), $this->anaylizeSupportedDatabases());
```
That way it is clearer that we rely on the return of both methods