0.8.0 released

0.8.0 removes static usage of the class (since it was broken anyway).
Various documentation issues have been fixed.
The ability to automatically retry service calls when SimpleDB is temporarily unavailable has been added.
batchPutAttributes now rejects attempts to batch too many items together. There is now a const, SimpleDB::MAX_ITEM_BATCH_SIZE, that you can use to manage how many items you batch together.