clang-format 3.4 (new formula)

[tcr]

Adds clang-format, a precompiled binary and subset of the llvm+clang archive. A future (compiled!) clang+llvm formula could have this recipe depend on it.

[thughes]

@tcr Why was this closed?

[MikeMcQuaid]

We won't include any more precompiled binaries in core.

[tcr]

@thughes You can try brew tap tcr/tcr with https://github.com/tcr/homebrew-tcr for a straightforward solution, if you're interested in precompiled binaries still.

[thughes]

Thanks.