cindex.py: Allow to create a cursor from file/row/column

We add a constructor to create a SourceLocation from a position in
a file and we use this SourceLocation to retrieve a cursor.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@143322 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed