This will make it easier to convert crate_ctxt into a region pointer, since
there are functions that return crate contexts. There would be no way to type
these functions if crate_ctxt had to be an inferred region pointer.
This required changing almost all users of hashmaps to import the hashmap interface first.
The `size` member in the hashmap structure was renamed to `count` to work around a name conflict.
This required changing almost all users of hashmaps to import the hashmap interface first.
The `size` member in the hashmap structure was renamed to `count` to work around a name conflict.