README: rewrote the intro
README: rewrote the intro

appc/acbuild,dgonyeo/acbuild,joshix/acbuild,mikeln/acbuild,appc/acbuild,containers/build,dgonyeo/acbuild,jonboulle/acbuild,mikeln/acbuild,asbachb/acbuild,containers/build,jonboulle/acbuild,asbachb/acbuild,joshix/acbuild