530 respect aliases, 426 allow using wildcards

Two fixes in one:
- #530 ```.use()``` method now respects the aliases defined in ```registerAvailableLanguageKeys()```
```
$translateProvider.registerAvailableLanguageKeys(['en', 'de', 'tr_TR], {
  'en_US': 'en',
  'en_GB': 'en',
  'de_DE': 'de',
  'de_CH': 'de
});

...

$translate.use('en_GB'); //This will load 'en' instead of 'en_GB'
$translate.use('tr_TR'); // This will load 'tr_TR' as expected
```

- #426 ```registerAvailableLanguageKeys()``` now accepts wildcards
```
$translateProvider.registerAvailableLanguageKeys(['en', 'de_DE', 'tr_TR], {
  'en_*': 'en'
});

...

$translate.use('en_GB'); //This will load 'en' instead of 'en_GB'
$translate.use('en_US'); //This will load 'en' as well, instead of 'en_US'
$translate.use('tr_TR'); // This will load 'tr_TR' as expected
```