Make AppVeyor create relocable packages as artifacts

[mwu-tow]

Basically we want not only to have AppVeyor building the project but also package it into relocable package. This task includes:

• manually creating and uploading somewhare package with dependencies (automating build of dependencies and packaging them is not part of this task)
• writing a Haskell script that will be invoked by AppVeyor — the script should build Dataframes and package binaries into relocable package

The script for now can contain hardcoded, Windows-specific steps (though it should be written with portability in mind from the beginning).