md5sha1sum: use brewed OpenSSL, simplify formula

Use homebrew's OpenSSL, remove explicit ```SSLINCPATH```, ```make install``` instead of manually copying binaries, change single quotes to double.

I tested each command on ten files between 60MB and 80MB, and the binaries linked against Homebrew's OpenSSL were about 30%-40% faster than the ones using Yosemite's.