* 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.
* deprecate Data.Nat.Order.decideLTE
* Add properties for LTE/GTE that produce the difference.
* remove deprecated function now that it is available in the base library.
* remove two deprecated lines.
* remove module deprecated since v0.4.0
* fix prelude reference to renamed primitive.
* finish removing Data.Num.Implementations
* remove deprecated dirEntry function.
* remove deprecated fastAppend. Update CHANGELOG.
* replace fastAppend in test case
* replace fastAppend uses in compiler.
* remove new properties that weren't actually very new.
* [ breaking ] remove parsing of dangling binders
It used to be the case that
```
ID : Type -> Type
ID a = a
test : ID (a : Type) -> a -> a
test = \ a, x => x
```
and
```
head : List $ a -> Maybe a
head [] = Nothing
head (x :: _) = Just x
```
were accepted but these are now rejected because:
* `ID (a : Type) -> a -> a` is parsed as `(ID (a : Type)) -> a -> a`
* `List $ a -> Maybe a` is parsed as `List (a -> Maybe a)`
Similarly if you want to use a lambda / rewrite / let expression as
part of the last argument of an application, the use of `$` or parens
is now mandatory.
This should hopefully allow us to make progress on #1703
