Correctly calculate OriginalColumn after multi-line tokens.

Summary: This also unifies the handling of escaped newlines for all tokens.

Reviewers: djasper

Reviewed By: djasper

CC: cfe-commits, klimek

Differential Revision: http://llvm-reviews.chandlerc.com/D1638

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@190405 91177308-0d34-0410-b5e6-96231b3b80d8