Merge branch 'master' of https://github.com/kirelagin/PrefixExpEval
Merge branch 'master' of https://github.com/kirelagin/PrefixExpEval
abstract worker
Revert "abstract worker"

This reverts commit 9ae68d8c27e31e7f65e498105c742e0fda1cbbc0.
Fix and clean up PostfixExpParserTest
Abstract Worker

Clses #8
Use blocking queue API in Worker

Closes #10
Closes #9