update README

@atrament/core 1.3.0

@atrament/core 1.2.2

Atrament-core 1.2 (#18)

* improved sound and music handling

Merge pull request #17 from technix/1.1

1.1

update readme

atrament 0.5.0

atrament 0.4

Atrament 0.3.0

Atrament 0.2.1