Correct on_load codegen

Local, non-tail calls for modules w/on_load was
not going indirect, thus such call sites could
not be rewritten in response to loading a NIF.
More Erjang/NIF functionality

- NIF resource pretty print module/resource_type
- NIF environment knows the value of self()
- Module environment correctly retains
  CreateGlobalRef's terms created during init.
-
Fix efile_drv ABI; was incorrect posixtime

We were assuming posixtime as millis since
1970-01-01 UTC; it should be secods since then.