Fixed Layout

enhanced the overall performance.
enhanced the page transition speed in PageTransition.NONE.
fixed the bug that flickering happens whenever page is tunred in PageTransition.Curl.
fixed the bug that ItemRef which has ‘linear no’ property shows.
tuned for the books which are created by NamoAuthor epub3 software.

MagazineActivity.java in Advanced demo
fixed the bug that Thumbnail images are not be released after leaving Activity so that app crashes by OOM.