timestamp has been added to grp sync item
updated data service and grps to deal with this
added msg and grp meta types which serves to hold meta data of grp and msg
removed observer temporarily
updated nxs item tests, need to update data service tests
git-svn-id: http://svn.code.sf.net/p/retroshare/code/branches/v0.5-new_cache_system@5256 b45a01b8-16f6-495d-af2f-9b41ad6348cc
added orig msgid and removed sign from nxsmsg, renamed nxsitems more appropriately
added more code to nxs net service
removed msg versioning from data service and added extra msgField
modified nxsitem test and datastore service appropriately, all pass
added serialisation of transactions and added transaction number to nxsitems
git-svn-id: http://svn.code.sf.net/p/retroshare/code/branches/v0.5-new_cache_system@5215 b45a01b8-16f6-495d-af2f-9b41ad6348cc