Code review comment for lp:~drizzle-pbxt/drizzle/drizzle-pbxt-2

This is the current merge of the PBXT storage engine into Drizzle (revision #1039). I re-merged (using to Stewart's method) after the move of the storage engines to the plugin directory, to ensure the entire PBXT change history is included.

So bazaar merging PBXT works on this tree. i.e. in the root directory:
bzr merge lp:pbxt
correctly merges the PBXT trunk into the plugin/pbxt directory.

I have also checked the following:

- Compiles and runs on Linux, Solaris and Mac OS.
- All tests run though using: ./dtr --engine=pbxt
- Compiles and runs without atomic ops if not supported.
- Performance (lp:~drizzle-developers/sysbench/trunk) also looks OK.

Let me know if anything is missing :)