Per code review: \

* hide the compatibility option \
* Make static things static \
* Use cl::extrahelp instead of cl::MoreHelp (defunct) \
* Use cl::PrintHelpMessage instead of our own printUse function \
* Use a std::set<sys::Path> for the path list because its now required by \
  the sys::Path class and also ensues directories are traversed in sorted \
  order.\
* Implement symbol table printing locally instead of in libLLVMArchive \
* Adjust to changes in llvm::Archive interface \
* Make sure we destruct objects even if exceptions occur. \
* Fix a typo in an output string.

llvm-svn: 17877