* Setting $ProgressPreference to SilentlyContinue makes no difference
when -EncodedCommand is used - any output to the progress stream
still appears on stderr.
* Delete file containing encode/decode functions since we no longer
need them.
* Fixes leak of output on progress streams for both normal and elevated
commands.
* Since we no longer base64 encode, ensure any characters special to XML
are correctly escaped in the elevated command. This ensures correct
parsing once the command is wrapped within the elevatedTemplates XML
based Task Scheduler definition.
Fixes#4322
2a060adbf8