v0.4.1

Script tags have been added.
There is now a very small set of tags that can be used in scripts to reference deployment data. For example, to get the configured PHP binary, you can use @php in a script. The same is try for @composer and there is a @release to get the latest release ID.
Wrote a new ScriptCompiler class to do the actual script translation.
There is a new documentation site at https://tpg.github.io/attache.