Position unittests just after `emplace` they test
Divide unittest and position its parts just after `emplace` they test
Refactor `emplace`
Fix `emplace` issue with structs with disabled ctors
Fix `emplace` part of issue 6436

* Issue URL: http://d.puremagic.com/issues/show_bug.cgi?id=6436
Create `std.traits.classInstanceAlignment`
Segregate `std.conv.testEmplaceChunk` function
Fix Issue 6635 - std.conv.emplace: enforcement is too weak

* Issue URL: http://d.puremagic.com/issues/show_bug.cgi?id=6635
Fix Issue 6436 - Refcounted initialization bug

* Issue URL: http://d.puremagic.com/issues/show_bug.cgi?id=6436
Fix terrible `std.typecons.scoped` bug

For misaligned buffer it emplaces object to incorrect memory location.
Fix `std.typecons.scoped` issue similar to `RefCounted` issue 6436.

* Issue URL: http://d.puremagic.com/issues/show_bug.cgi?id=6436
Add comments to `emplace` unittests
Improve `emplace` unittests
Fix bug 8900 - Zip with infinite range fails.

`std.range.Zip` contains a `Tuple`, whose `toString()` function calls `formatElement` which eventually calls this function, leading to a static call to `walkLength` on infinite ranges. Since pul request 880, `walkLength` doesn't work with infinite ranges, so it fails to compile.

This change ensures that `walkLength` is called with only valid range types.

Bug: http://d.puremagic.com/issues/show_bug.cgi?id=8900
Add unittest for `emplace` with struct without constructor
Fix `std.typecons.scoped` name clashes issue

One was unable to call `alignment` or `aligned` class members because `Scoped(T)` struct has such private members and name lookup is done before protection resolution.
Remove outdated comment from `std.typecons.scoped` unittest.
Added unittests for fixed `std.typecons.scoped` alignment issue.

* issue fixed in commit 9cf123aff32a09cc766202bef13a77c6c1a05e21
Added unittests for fixed `std.typecons.scoped` initialization issue.

* issue fixed in commit 2840e44b21a3e5617069a1fd7f894282e229e48c
Workaround for an issue on Posix that fails b3d3c44cc1e879b6ca6850abf94df5ffb6fc37b0 with the following linker error:

generated/linux/debug/32/unittest/std/typecons.o: In function `_D3std8typecons51__T6scopedTC3std8typecons18__unittestL3287_53FZv1AZ6scopedFZS3std8typecons51__T6scopedTC3std8typecons18__unittestL3287_53FZv1AZ6scoped51__T6ScopedTC3std8typecons18__unittestL3287_53FZv1AZ6Scoped51__T6ScopedTC3std8typecons18__unittestL3287_53FZv1AZ6Scoped14Scoped_payloadMNgFNdZNgC3std8typecons18__unittestL3287_53FZv1A':
/home/braddr/sandbox/d/d-tester/client/pull-346162/phobos/std/typecons.d:3090: undefined reference to `_D3std8typecons51__T6scopedTC3std8typecons18__unittestL3287_53FZv1AZ6scopedFZS3std8typecons51__T6scopedTC3std8typecons18__unittestL3287_53FZv1AZ6scoped51__T6ScopedTC3std8typecons18__unittestL3287_53FZv1AZ6Scoped7alignedFkZk'