Don't use built-in .sort in std.base64 unittests
Preemptive fix of other places where .sort is used
Merge pull request #2565 from quickfur/std_base64_sort

Don't use built-in .sort in std.base64 and other places
Fix 9906: unaryFun and binaryFun should recognize static opCall

Structs or classes with static `opCall` should be recognized as valid
function objects.
Update ddocs.
Revert AA/array extension to unaryFun.

Per PR discussion.