* jchoover: Switch WixBA over to using engine updates. Fixed several small issues with atom feed parsing.

- FileVersionFromString now handles a 'v' prefix
- ProcessEntry - Copy the value of the content to the update entries content, not the type.
- ApupAllocChainFromAtom - Only include valid entries in the update chain, and free any memory allocated for failed entries.
- ApupFreeChain - Free memory behind rgEntries