Updated feature: Gleez Mango_Collection v0.6.0

+ Mango_Collection::getNext - Implement [MongoCursor::getNext]
  so that the return value is a [Mango_Document] instead of array
+ Mango_Collection::hasNext - Implement [MongoCursor::hasNext]
  to ensure that the cursor is loaded
+ Mango_Collection::getModel - Get an instance of the corresponding
  document model
+ Mango_Collection::$_model - The class name or instance of the
  corresponding document model or NULL if direct mode
+ Mango_Collection::$_models - A cache of [Mango_Document] model
  instances for performance

Update feature
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+ Mango_Collection::getFieldName - Used $this->_model
+ Mango_Collection::__construct - New constructor semantic

Fixed issue
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+ Fixed PHPDoc

New dependencies
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+ Mango_Document
New feature: Added initial Mango_Document. WIP