Hallmark continues its participation at the nation’s largest pop culture fan gatherings with Hallmark Keepsake Ornaments and itty bittys® plush collectibles exclusively developed for 2015 events. As previously announced, a pair of Keepsake Ornaments and a pair of itty bittys will be sold this week in limited quantities at Star Wars Celebration, scheduled April 16-19 in Anaheim, Calif.: An Epic Vision is the name of the Keepsake Ornament two-pack that features Luke Skywalker and Darth Vader locked in a heated…