Add a "keep-unicode-literals" option (still many problems with unicode minimize)

[jogibear9988]

Would it be possible to add a keep unicode literals option?

There are still many errors with unicode literals and minimize.

see:

#627
https://github.com/Polymer/polymer-cli/issues/886
https://github.com/Polymer/polymer-cli/issues/633
https://github.com/Polymer/polymer-cli/issues/701

[boopathi]

This is fixed in #730

[jogibear9988]

i think Polymer/polymer-cli#886 is not yet solved