reverting the reorganization done in 3455-3456 in order to make merging my experimental branch to trunk easier.

Preparation for new organization of code in to sub packages. Changed autoload() to work with new structure.

updated NestedSet to use Zend coding standards.  still a few problems with return values using () that need to be looked at.

joesimms: initial draft for tree support. NestedSet support included, placeholders for other popular implementations also included. Read the README.tree file for more information and changelog to core files. Modified core files have also been included in this commit. hope it works and you like it !

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removing the closing PHP tags form all php files, it\'s not needed and can break sessions which are whitespace sensitive

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