bowling: Add problem description
bowling: Add C solution
bowling: Correct scoring of spares

A simple typo caused spares to be counted incorrectly. The spares test
case, coincidentally, evaluated to the correct score despite the bug.
Add a test case to expose the problem and correct the bug.
bowling: Compile with -Wall -Werror -Wextra

Correct the following error by including a default case:

bowling.c:17:1: error: control reaches end of non-void function [-Werror=return-type]
bowling: Add two Haskell solutions