iterator_proxy: added description comment.
Log: renamed report_error(std::exception_ptr) to report_error_ptr(); changed imports.¹

1: report_error() funcs are now part of the Log namespace.
Too many changes made lately, so master is broken for a bit.
IO::FlatDatstore: added index serialization; create stub if non-existent when opening; updated interface.
Nuked Net stuff;¹ moved session stuff to System; started UI & session handling for Client.

Client:
	added --no-stdout and encapsulated stdout toggling;
	added some UI rudiments: view container, command line status label;
	changed config prop names for sessions;
	load & keep sessions in config order.

System: added classes Session and SessionManager to replace Net::Session.

utility: imported duct::bit().

premake_common: linked boost_filesystem.

1: Commands are no longer transactional, and networking won't
be used for a long while, if at all.