Patch: Threads and RawData

[Bryce McKinlay]

RawData fields are fields that don't get marked by the garbage
collector. In java.lang.Thread, the "data" field is used to store a
native struct containing native thread fields. However, we allocate
"data" through the collector! That means crashes in threaded programs.

This patch changes "data" to Object, and changes the documentation for
RawData to better reflect what it actually does.

I have checked this in.

regards

  [ bryce ]