Refactor Image Cache methods into a singleton class.

- Create new singleton class for ImageCache management.
- Update method calls to ImageCacheManager singleton.
- Rename ViewController method.
Create Manager class to handle the iOS Twitter Accounts.

- Add new class, TwitterAccountManager, as a singleton class.
- Move the methods to get Twitter Accounts from iOS into new class.
- Update references in AppDelegate.
Design UITableViewCell in subclass, AccountListTableViewCell.

Set the Username for the Twitter Account and the Profile Image
in the custom UITableViewCell.

- Create new class, AccountListTableViewCell, to generate UITableViewCell.
- Update retrieveCachedProfileImage to return UIImage object.
- Change references to retrieveCachedProfileImage.
- Set the new custom TableViewCell in AccountsListTableViewController.
Abstract handling of network API requests to Twitter.

- Create PPSDownloadProfileImageManager to download image.
- Update referneces to use the new Manager class.
- Add the Network Status Indicator when the request goes out.
- Create method to download images for all Twitter accounts.
- Reorganize the import statements.
Attempt to retrieve all images for Accounts on app load.

When the application finishes setting up the views, call the
getProfileImagesForAllTwitterAccounts off of the main thread
and then send out a notification that the images were updated.
The project will use the cache as the primary store to grab the
images from. The TableView and AccountView will observe for the
notification and remove the observer when the view unloads.

- Update App Delegate to retrieve all profile images.
- Add NSNotificationCenter observers to TableView and AccountView.
- Create selector methods to handle a notification posting.
- Post a notification after storing the image in cache.
Redesign the custom table view cell.

NOTE - The Full Name Label was added but is not currently
set with a valid value. The ACAccount is not storing the
user full name so it will need to be retrieved similar
to how the profile image URL.

- Add circle frame around the profile image.
- Change the separator inset to account for profile image size.
- Change sizing of the profile image view.
- Add User Full Name label and set with dummy value.
Make classes more readable with pragma mark.

- Add pragma marks to define sections in each class.
- Move methods around to fit in each pragma mark section.
- Reorder the #import statements and organize for readability.
- Refactor AppDelegate to process functionality in specific methods.
- Include Accounts/Accounts.h import for ProfileImgMgr.
Refactor ImageManager into ProfileDetailsManager.

The class to handle downloading images should really
grab the profile details from the JSON data in the
request.

- Rename the ImageManager class to handle Profile Details.
- Move the download image work into getTwitterProfileImageForTwitterAccount.
- Change the method names.
Store certain details about Twitter account.

When downloading the data from Twitter on application
load, the app will create a new instance of the
TwitterAccountDetails model which stores a few properties
from the Twitter account. These will ultimately be cached
to disk and shown in the UI.

- Create new models class, PPSTwitterAccountDetails.
- Send the request data into new instance of model.
Add methods to store the details to disk.

- For now, call save to disk method after downloading data.
- Add public method to save object instance to disk.
- Create private method for path to file location.
Use constants to define keys in AccountDetails.
Setup groundwork to get Profile details throughtout app.

- Change the NSNotification name to better reflect action.
- Store the twitter accounts retrieved in a dictionary.
- Add the dictionary to AccountView.
- Create labels for the Full Name title and value.