Make sure all print statements are compatible with Python 2 and Python3 using
the `from __future__ import print_function` statement.
Differential Revision: https://reviews.llvm.org/D56249
llvm-svn: 350307
* Linters now return their information instead of printing it, to
enable easier unittesting
* Added support for finding tabs in files, added to C++ linter
llvm-svn: 65202
