ZF-414: Add getSectionName() and areAllSectionsLoaded() methods
These methods will allow for easy retrieval of the way that the Zend_Config instance was loaded without having to store it outside the class. This is particularly useful where a Zend_Config object instance is stored and fetched using an application registry.
getSectionName() will return either a string or an array of string depending on how the Zend_Config was loaded. If it was loaded using a single section name, then getSectionName() will return a string. If it was loaded using mutliple section names or null (all sections) then it will return an array.
areAllSectionsLoaded() will return a boolean to indicate if the entire ini file was loaded.