Improvements to xl backend and 64-bit suspend/resume

Merge pull request #111 from robhoes/xl-sync

Some further libxl backend tweaks

The no-more-re.str release

Merge pull request #75 from jonludlam/0.9.37-release

0.9.37 release

0.9.34

Merge dead-end 0.9.32 branch into 0.9.33