Merge pull request #192 from garyb/master

Update psc options to allow main module to be specified and multiple modules to be kept by DCE
Traverse top-down in replaceTypeClassDictionaries, to avoid traversing the wrong part of the AST, for an approx 30% performance improvement when using type classes.
Update and rename RELEASE.md to RELEASE-0.3.md
Create RELEASE-0.2.md
Create RELEASE-0.4.md
Bump version to 0.4.0
Update RELEASE-0.4.md
Update conf.py