The use of `cindent(1)` and `indent(1)` by the IOCCC Judges
during final round processing has been deprecated in favor
of the `clang-format(1)` tool.
Removed rules in `1337.mk` related to `cindent(1)` and `indent(1)`.
Added `make clang-format` rule to `1337.mk`.
Added `${CLANG_FORMAT}` Makefile variable to `var.mk`.
Created `.clang-format` to hold the IOCCC style, a style that
is somewhat similar to the Linux Kernel style.
