Add support to print version.

Summary: Add support in the universal driver to print the lld version and the
repository version.

Test Plan: A driver test is added

Reviewers: kledzik, ruiu

Reviewed By: ruiu

Subscribers: llvm-commits

Projects: #lld

Differential Revision: http://reviews.llvm.org/D5641

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@219277 91177308-0d34-0410-b5e6-96231b3b80d8