Publish 0.7.0-alpha (#53)
Publish 0.7.0-alpha (#53)

This is nowhere near ready for 0.7.0, but releasing an alpha release
allows Fuchsia to vendor zerocopy and remove their in-tree copy
(zerocopy used to live in the Fuchsia tree before it migrated to
GitHub).

Closes #52
google/zerocopy,google/zerocopy