added check to wait for required number of free ring slots
Merge pull request #46 from balrajsingh/master

Added check to wait for required number of ring slots before writing
Make Io_page in the UNIX backend compatible with Io_page in the Xen backend.
Fix unikernel generation with gcc 4.8.
release 0.9.2
make Evtchn use a little safer (even though it's currently a noop), since it should be initialized before the runloop in case devices register anything in the library initializers
tweak CHANGES