issue 4916
Fix appender form elaborate assign types
More unittest for appender
tweak appender, add unittests for not-yet covered paths
Add missing file I/O functions for Win64 DMD and Windows LDC
Fixes Issue 11339 - Add examples for ElementEncodingType and ElementType.
Merge pull request #1538 from dymk/win64-fileio

Fix Issue 10227: Add missing file I/O functions for Win64 DMD and Windows LDC
Merge pull request #1660 from AndrejMitrovic/Fix11339

Issue 11339 - Add examples for ElementEncodingType and ElementType
Merge pull request #1152 from andralex/4916

Fix Issue 4916: struct VariantN does not overload ()
Fix missing `void back(bool)` in Array!bool.Range

Forked from #1010

Also some cleanup:
changed ulong to size_t, some spaces, some Tuples, some "!(T)"=>"!T"
Merge pull request #1656 from monarchdodra/boolArrayBack

Fix missing `void back(bool)` in Array!bool.Range
Changed to return uninitialized Variant when the stored function returns void.
Add unittests for issue 11360.
Slightly reworded comment.
Fix issue 11361 - Variant fails to compile with delegates containing const arguments.
Merge pull request #1666 from Kapps/fix11360

Fix issue 11360 - Function pointers / delegates returning void fail to compile with Variant.
Resolve merge conflict.
Merge pull request #1667 from Kapps/fix11361

Fix issue 11361 - Variant fails to compile with functions containing const arguments.
Merge pull request #1529 from monarchdodra/appenderEmplace

Fix appender form elaborate assign types