feature/append connection

[CristianLlanos]

• Added PhpTypeEnum::absentTypeEnum() to support properties with no type such as Eloquent's $table and $connection properties
• SchemaBlueprint now has the connection name from which it was analyzed. It has also been given SchemaBlueprint::getConnectionName() and SchemaBlueprint::setConnectionName()
• The AppendConnection key has been added to the reliese.php config file to support appending the $connection property to generated models
• ClassFormatter::formatProperty() has been updated to account for property without types
• The ModelGeneratorConfiguration constructor now handles default values when possible
• Behat and PhpUnit tests have been updated to support appending the $connection property to Eloquent models