Do not use pipes for building & uploading packages because:
* They spawn more jobs on Bintray for metadata generation - each upload is
done in a separate session.
* Bintray doesn't handle well concurrent uploads and metadata can be corrupted.
This happened in all recent builds of platform independent packages - in
each upload task file had a same name and that triggered problem with metadata.
* Using delays for workaround for a problem described above works, but isn't
safe.
