2421: refactor CssLayoutEngine
 2422: refactor
2422: refactor
2425: refactor
2428: TextContentManager
2429: fix CssSpec

after change style
curSpec.VersionNumber++; //***
2431:CssBox's CalculationEpisode
2433: refactor
2434: refactor
Merge branch 'v1.7dev' into v1.7