Integration scripts for Clang's Modernize and Tidy tool.

New directory: `scripts/`, in which small scripts for developers reside.

- `modernize`: runs all cpp files through `clang-modernize`, respecting
  out targeted compiler versions, applying C++11 transformations, doing
  syntax checks and formatting --- in parallel.

- `tidy`: runs all cpp files through `clang-tidy`, with selected
  warnings only, since we do not want to warn on every small detail.

Please check the talk slides for `clang-tidy` linked in the references!

References:

- http://clang.llvm.org/extra/clang-tidy/
- http://llvm.org/devmtg/2014-04/PDFs/Talks/clang-tidy%20LLVM%20Euro%202014.pdf
- http://clang.llvm.org/extra/clang-tidy/checks/list.html
- https://github.com/Project-OSRM/osrm-backend/pull/1603

scripts/tidy.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+# Runs the Clang Tidy Tool in parallel on the code base.
+# Requires a compilation database in the build directory.
+
+git ls-files '*.cpp' | grep -v third_party | xargs -I{} -P $(nproc) clang-tidy -p build -header-filter='.*' {}