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