AutocompletionTableViewDelegate

This simply adds a new _delegate_ that allows suggestions to be generated on run-time from _DB_ or _HTTP service_.
It also notifies the caller of which suggestion was clicked.

```objective-c
/* AutocompletionTableViewDelegate */
- (NSArray*) suggestionsFor:(NSString*) string;
- (void) didSelectAutoCompleteSuggestionWithIndex:(NSInteger) index;
```
Example was also updated to use the delegate. Notice that the initial set of  ```suggestionsDictionary``` is now redundant:

 ```objective-c
_autoCompleter.suggestionsDictionary = [NSArray arrayWithObjects:@"hostel",@"caret",@"carrot",@"house",@"horse", nil];
```