Adding in parsing and the start of semantic support for __sptr and __uptr pointer type qualifiers.  This patch also fixes the correlated __ptr32 and __ptr64 pointer qualifiers so that they are truly type attributes instead of declaration attributes.

For more information about __sptr and __uptr, see MSDN: http://msdn.microsoft.com/en-us/library/aa983399.aspx

Patch reviewed by Richard Smith.
Minor fix to comment from my previous commit.