Use rawgit.com for the rendered links

Now that we have two branches of the TS, we can't easily use `gh-pages` anymore.
Rename mods.allocator.uses to allocator.uses.trait.
Use a real reference for BinaryTypeTrait.
Section references are now against the C++14 DIS.
Put a missed string_view table caption in code font.
Number and caption the new optional<> tables.
Use std::move() instead of move() in optional<>.
Insert "Then" at the beginning of [meta.trans.other] p6 b3.
It's <cxx-postconditions>, not <cxx-postcondition>.

Filed cplusplus/html-doc-framework#12.
Change alg.search to "Equivalent to *return*".
Update the doc framework and regenerate the index and standalone document.
Fix a table border.
Commit a draft of the PDTS.