Updated Gap5 to support a richer list of machine platforms in the SAM
@RG tag.

(Ongoing: the platform type can also now be edited, but not yet saved,
in the ListLibraries window.)


git-svn-id: svn://svn.code.sf.net/p/staden/code/staden@3708 ba6f2710-ca9f-427c-89d3-5bf716dbc8e1