Typo fix + note calling then() multiple times ok

Hat tip Evan Goer and Marco Asbreuk, respectively. I hope I spelled
Marco's name right.
Fix a typo in css section of full source code.

See http://yuilibrary.com/forum/viewtopic.php?p=38789#p38789
Merge pull request #588 from albertosantini/fix-typo-masterdetail-example

Fix a typo in css section of full source code.
Stop modifying people's `options` objects passed to Model's `setAttrs()`

This fixes an issue where people's `options` objects were being modified
by Model's `setAttrs()` method which was adding the `_transaction` to
their object. Now a shallow copy of the `options` object is created
before it is modified.

Fixes #598
Update Model's change history
Correct a Model change history entry
Merge branch 'live-docs' into dev-master
Merge branch 'model-sync-options' into dev-master
Build Model
Build Loader and Seed for Gallery bump