Lots of changes around memory managment in the Runtime. Added memory regions and fixed race caused by calling rust_srv::malloc() from multiple threads when sending messages.

Add a "special" rust_log flag to be used for debugging in cases where the full log output prevents races from occurring.

Add support for a reserved-words list and reserve the various not-supported-but-plausible IEEE datatypes.

Putting out the burning tree on Windows. Turns out you can completely starve threads by not yielding on windows/vmware, really weird.

Absent any deep overhauls to syntax or constant-handling, hack in the ability to project a cexp var binding to a token in the parser. Use it in comp/rustc.rc and comp/lib/llvm.rs.

Fix max_sz bug that ended up causing us to index incorrectly into a vec of tag types.  Add a testcase.

Ignore upcall_flush for channels that are disassociated from ports. This makes task-comm-10 break a little less hard, but it still leaks because messages pending in the channel are never freed.

Add native vec[u8] to str converter.  Put in workaround for leak in str to vec[u8] converter.  Add testcase exercising both.  Drive-by fix a potential array-out-of-bounds write on rust_str buffers.