Delay in 1.0 release

I've decided to go back to pre-1.0 versions because I'm upgrading to the latest major version of the wxPython GUI toolkit. Among the many advantages: it's pip installable, so Linux users will then be able to pip install omnivore!

This version is still broken in a number of ways, so stay at the 1.0rcX for the moment unless you want to test the bleeding edge.