Initial code for remote debuginfo server.  Handles all ELF/Dwarf{2,3,4}
on Linux.  No Dwarf1, no Stabs, and MacOSX probably won't build.


git-svn-id: svn://svn.valgrind.org/valgrind/branches/DISRV@13423 a5019735-40e9-0310-863c-91ae7b9d1cf9