web.ExcludeFromOfflineClient property with CMOS

We are right now collecting all the APIs which are available from SB assembly, but not in the CSOM, so looking on getting this introduced sooner or later. In general would also suggest to submit user voice entries for these kind of gaps from http://sharepoint.uservoice.com/, so that they are processed accordingly. Due removal of code-behind sandbox support from the SharePoint Online, we will ensure that this will be on the prioritized list of what's available in SB, but not in CSOM.