[Update] IronPython to version 3.4.0

[samatstariongroup]

Prerequisites

• [x] I have written a descriptive pull-request title
• [x] I have verified that there are no overlapping pull-requests open
• [x] I have verified that I am following the COMET-IME code style guidelines
• [x] I have provided test coverage for my change (where applicable)

Description

An update of IronPython to version 3.4 (from 2.7) as well updates to AvalonEdit dependencies for reporting and scripting. This one requires manual testing of scripting and reporting