Add a clang-format file approximating the c style guide

[TysonAndre]

This detects some inconsistent uses of indentation and inconsistent space after casts, but has a lot more false positives.

https://clang.llvm.org/docs/ClangFormat.html#script-for-patch-reformatting may be of use for saving time for contributors reformatting new patches

Problem

Make it easier to automatically detect and automatically fix violations of the style guide in new patches

Solution

Add an example .clang-format.example file for use with clang-format