javascript: skip folding002 test
Add 'covering' function option

Checks a function and all descendents cover all inputs (without worrying
about termination, just that inputs are covered in case clauses).

Primary intention of this is to guarantee that all error cases are
handled, especially in state transitions in effects.
Show argument names in :doc

Now, :doc will show the names of any documented arguments, even if they
are not used in the body.

Fixes #1000.
Stop showing __pi_arg and MNs in docs
Insert U, UL, and ULL suffixes in C

Now, generated C constants for Bits8, Bits16, Bits32, and Bits64 get the
appropriate suffixes for unsignedness and longness (-U, -U, -UL, -ULL,
respectively). This gets rid of warnings and fixes #932.
Fixing the build.
Revert the trifecta change.
Only show documented arguments in :doc

This reduces redundancy, avoids showing internal names like __pi_arg,
and takes up less space. New output:

    Idris> :doc foldl
    foldl : Foldable t => (acc -> elt -> acc) -> acc -> (t elt) -> acc

    Idris> :doc id
    id : a -> a
        Identity function.

    Idris> :doc the
    the : (a : Type) -> (x : a) -> a
        Manually assign a type to an expression.
        Arguments:
            a : Type  -- the type to assign

            x : a  -- the element to get the type
Merge pull request #1004 from gabemc/issue/1003

Fixing the build.
Merge pull request #999 from raichoo/javascript

javascript: skip folding002 test
Merge pull request #1001 from david-christiansen/doc-arg-names

Show argument names in :doc, and don't show undocumented args
Merge pull request #1002 from david-christiansen/issue/932

Insert U, UL, and ULL suffixes in C
Rename UnusedArgs to Erasure.
Remove export of traceUnused.
Simplify unused arg search.
Cleanup and purification in Erasure.hs.
More purification.
Simplification with pattern guards.
findUsed stub written.
Make ProjCase take exactly one alternative.   (TODO: is this safe?)