Documentation cleanup:

* Primarily fixed \param commands with names not matching any actual
  parameters of the documented functions.  In many cases this consists
  just of fixing up the parameter name in the \param to match the code,
  in some it means deleting obsolete documentation and occasionally it
  means documenting the parameter that has replaced the older one that
  was documented, which sometimes means some simple reverse-engineering
  of the docs from the implementation;
* Fixed \param ParamName [out] to the correct format with [out] before
  the parameter name;
* Fixed some \brief summaries.

llvm-svn: 158980