The finishing touches on getting the compact unwind dumping completed

The finishing touches on getting the compact unwind dumping completed
for x86_64.  i386, arm, arm64 aren't handled yet but those are minor
variations on this format.

This commit also adds code to read the symbol table out of the
binary and read the LC_FUNCTION_STARTS to augment the symbol table
with the start addresses of all the functions - and print the
function names when showing the unwind info.

llvm-svn: 222951