Added script for automating releases.
Updated IE public build script to use MILESTONE_VERSION.

Also added comment clarifying that we only use the script for building dependencies at present.
Renamed IE publicBuild script to publicDependenciesBuild.

Because that's what we use it for now.
Added script for automating public releases at IE.

This uses the standard release script for doing the work. We can't use that directly at IE because we need to bypass custom wrappers to get a vanilla build environment.
Merge pull request #1103 from johnhaddon/publicBuild

Public build scripts