#853: data models and database structure updated.
#853: sitemaps list added to site settings.
#853: sitemap editing dialog updated.
#853: site map creation added.
#853: site map deleting added.
#853: site map deleting updated.
#853: events SitemapCreated and SitemapDeleted added.
#853: page placement into site map updated.
#853: page placement into site map updated.
#853: sitemap getting and saving updated.
#853: new page placement into the sitemaps updated.
#853: page.NodeCountInSitemap calculation updated.
#853: check if page is in the sitemap moved to be checked on the fly.
#853: page accessor updated.
#853: page delete updated.
#853: notifications about updated site map nodes added.
#853: sitemap history (initial version).
Merge branch 'dev' into dev-multiple-sitemaps

Conflicts:
	Modules/BetterCms.Module.Pages/BetterCms.Module.Pages.csproj
	Modules/BetterCms.Module.Pages/Command/Page/GetPagesList/GetPagesListCommand.cs
	Modules/BetterCms.Module.Pages/Command/Page/SavePageProperties/SavePagePropertiesCommand.cs
#853: missing resource file added.
#853: history dialog events added.