* contrib library unused import removal
* remove a few unused imports.
* another round of unused import removal
* another round of unused import deletion.
* another round of unused import deletion.
This was taking too long, and adding too many things, because it was
going too deep in the name of having everything accessible at the REPL
and for the compiler. So, it's done a bit differently now, only chasing
everything on a "full" load (i.e., final load at the REPL)
This has some effects:
+ As systems get bigger, load time gets better (on my machine, checking
Idris.Main now takes 52s from scratch, down from 76s)
+ You might find import errors that you didn't previously get, because
things were being imported that shouldn't have been. The new way is
correct!
An unfortunate effect is that sometimes you end up getting "undefined
name" errors even if you didn't explicitly use the name, because
sometimes a module uses a name from another module in a type, which then
gets exported, and eventually needs to be reduced. This mostly happens
because there is a compile time check that should be done which I
haven't implemented yet. That is, public export definitions should only
be allowed to use names that are also public export. I'll get to this
soon.
As in Idris 1 - if an interface declares a method as total or covering,
then all implementations have to satisfy that.
Temporarily turn off %default directive again, at least until totality
checking works as it should (this is probably better than removing it
from various places because I'll forget to put them back)
This means temporarily removing some '%default total' from the libraries
and tests, since the input for codata checking isn't right yet (it needs
appropriate use of inlining)
