Merge pull request #2 from jicama/gh-pages

decltype(auto) mangling
Clarify the ABI's treatment of POD types.
Clarify the mangling of pointer-to-member-function types
and reorganize and clarify the expression-mangling section.
Hoist some anchors up to their section headers.
There is no difference in the mangling of <type> and <member-type>,
I am just horribly misreading the old messages.  Apologies.
Per repeated discussion on cxx-abi-dev, remove the unwanted
"without leading zeroes" clause from the floating-point literal
mangling.

Generalize the wording a bit while I'm there.
Add changelog entries for everything in the git history
that isn't a very minor editorial change.
Minor formatting changes to the revision history.
Fix a pair of broken links: these should be anchors, not hrefs.
Add the mangling for literal operators proposed by
Sean Hunt on June 5th, 2011.
Add the mangling for null pointer template arguments proposed
by Jason Merrill on August 27th, 2011.
Formatting and self-links on anchors.
Pedantically clarify treatment of reference types.
Add mangling for dependent elaborated-type-specifiers.
Apply some editorial fixes suggested by Nicolas Guillemot.
Remove uses of "subclass".
Define behavior for variadic arguments of non-trivial type.