Adds instructions to fix problems with components that have transclus…

[aikeda]

Adds instructions to fix problems with components that have transclusion and a custom tag is present (e.g.: <accordion-title> within <sm-accordion-item> within <sm-accordion> )

Without this, your components won't work with angular 2.0.0+ final release (sept 14, 2016)

Fix found here: http://stackoverflow.com/questions/39428132/custom-elements-schema-added-to-ngmodule-schemas-still-showing-error