use alia-2.0.0-rc1

Hi @pry,

Late night PR. 
I updated Alia and simplified a lot of things. As a result the API is slightly different in some cases (got rid of kwarg in favors of maps, some fns are simplified and all dyn vars are gone). This makes Alia noticeably faster, I thought you might be interested. 

This PR is untested yet, but I figured I'd send it already. It's a bit late now but I plan on testing that later this week-end. 

The same kind of PR might land on pithos fairly soon too (work started on a branch already).

Cheers