20103 - Should handle the situation where iBL is unable to return an image
- Updated `getImage` within the `Elements` model to return a URL to the
  placeholder image (uploaded in separate PR)
- Updated the `ElementsTest` accordingly
20103 - Handle the situation where iBL is unable to return an image

- Created new static `Configuration` class, which is used to hold values
  specific to the client that are used by Bamboo objects; transferred all
  relevant members of the `Client` class to this class and associated unit
  tests were rewritten within `ConfigurationTest.php`.
- Added `$_placeholderImageUrl` member variable to the `Configuration`
  class, which is used to define the image that is used when iBL is unable
  to return an image.
- Updated `Elements.getImage()` and `Elements.getStandardImageRecipe()`
  to make use of `getPlaceholderImageUrl()` within `Configuration` class
Renamed `$l` in `ConfigurationTest.testSetCache` to `$clientListeners`
Moved duplicated code in `request` and `requestAll` to private method

- New method implemented as `_getRequestObject()`
Added `CounterTest.php` and made minor styling changes

- Adjusted spacing within `request` and `requestAll` methods
- Aligned values within array in `client->get` call within `getRequestObject`
Removed `getLogger` from `Configuration.php`

- Updated `ConfigurationTest.php` accordingly, using `assertAttributeEquals`
Added code for case where standard image is blank string

- Added check for whether `$this->_images->$type` is empty within
  `getStandardImageRecipe` and `getImage` in `Elements.php`
- Updated `ElementsTest.php` to cover all cases covered IPLAYER-20103
Merge pull request #104 from haslaa01/20103-responsive-web-should-handle-the-situation-where-ibl-is-unable-to-return-an-image

20103 responsive web should handle the situation where ibl is unable to return an image