Update to the latest release of ANTLR 4
Merge branch 'sharpen'
Fix build errors in newly generated code
Working on development version 4.2.2
Updated build dependencies
ST4 no longer requires a dummy template if the STG only contains an import
Update reference to obsolete method
Update CSharp.stg to match changes since 4.2.1
Updated version numbers for release 4.2.2-alpha001