Revamped partial function application

* moved internals into separate header i.e. the `detail` namespace relating to `Apply`
* implemented automatic alias selection by implementing aliae of the basic variadic `type` template alias in different base classes
** variadic partial application is implemented in `detail::apply_variadic`
*** `detail::apply_single` and `detail::apply_pair` define aliae to `detail::apply_variadic`'s `type` template alias
*** both restricted aliae derive from `detail::apply_variadic`
** `Apply` derives from any of the aliae defining base classes depending on the count of placeholders as determined by `detail::count_placeholders`
*** `Apply` is guaranteed to always be derived from `detail::apply_variadic` one way or the other
* changed functions, test cases and examples depending on `Apply` accordingly
** `Length` had to be reimplemented without `Apply` as it doesn't allow usage of aliae expecting a different count of arguments anymore
*** this is a advantage in the sense that core functionality of _TypeAsValue_ now doesn't depend on this complex partial application implementation anymore
*** such functionality may be reimplemented separately from `Apply`
* removed unnecessary `tav` namespace prefixes

1 files changed, 2 insertions, 2 deletions

diff --git a/test.cc b/test.cc
index 931d8f1..2bf9e09 100644
--- a/test.cc
+++ b/test.cc
@@ -999,7 +999,7 @@ static_assert(
 			tav::Multiply,
 			tav::Int<21>,
 			tav::_0
-		>::single_type<
+		>::type<
 			tav::Int<2>
 		>::type
 	>::value,
@@ -1014,7 +1014,7 @@ static_assert(
 				tav::Add,
 				tav::_0,
 				tav::Int<10>
-			>::single_type,
+			>::type,
 			tav::List<tav::Int<0>, tav::Int<2>, tav::Int<4>>::type
 		>::type
 	>::value,