Make the ParseObject construct throw more specific exceptions

[ghost]

In a scenario of a developer not utilizing ParseClient::initialize before calling another object such as new ParseUser(), the user receives a message about specifying a Parse class name or using ParseObject::create, throwing them in the wrong direction about their error. This commit adds one more line to the Exception asking them if they in fact remembered to use ParseClient::initialize before being thrown away from their obvious mistake - this should prevent questions like these or #55 from occurring.

The resulting Exception now displays as such:

[11-Nov-2014 20:19:34 Europe/Berlin] PHP Fatal error: Uncaught exception 'Exception' with message 'You must specify a Parse class name or register the appropriate subclass when creating a new Object. Use ParseObject::create to create a subclass object. Perhaps you forgot to use ParseClient::initialize before creating your Object?' in /Users/schuylerjager/Desktop/GitRepos/parse-test/parse-php-sdk/src/Parse/ParseObject.php:88
Stack trace:
0 /Users/schuylerjager/Desktop/GitRepos/parse-test/index.php(17): Parse\ParseObject->__construct()
1 {main}
thrown in /Users/schuylerjager/Desktop/GitRepos/parse-test/parse-php-sdk/src/Parse/ParseObject.php on line 88

[ghost]

Forgot that GitHub includes the latest commits in a Pull Request if not merged yet. I've modified my approach to use a new Exception instead of modifying the existing one which could cause confusion as to which mistake the developer has made. Now the user will see the following only if they fail to ParseClient::initialize:

[11-Nov-2014 20:34:18 Europe/Berlin] PHP Fatal error: Uncaught exception 'Exception' with message 'You must initialize the ParseClient using ParseClient::initialize and your Parse API keys before you can begin working with Objects.' in /Users/schuylerjager/Desktop/GitRepos/parse-test/parse-php-sdk/src/Parse/ParseObject.php:83
Stack trace:
0 /Users/schuylerjager/Desktop/GitRepos/parse-test/index.php(18): Parse\ParseObject->__construct()
1 {main} thrown in /Users/schuylerjager/Desktop/GitRepos/parse-test/parse-php-sdk/src/Parse/ParseObject.php on line 83

Sorry in advance for the multiple commits.

[gfosco]

Thanks. 👍