- avoid hashing Account* twice. one call to operator[] is sufficient.
- don't need use std::move with better constructors
- sanity check - can't have a budget with num_periods = 0
- remove unused headers
The root cause of which is that on recent releases of GLib (recent
meaning 2.66 in the current Debian stable!) g_type_instance_get_private
looks in the wrong place for the private data. When running the script
in question it returned NULL and since the code didn't check for a valid
pointer, it crashed.
So this change replaces all calls to g_type_instance_get_private with
the function [type_prefix]_get_instance_private() added in glib-2.36
except for two register2 files that have been removed from master; those
are ignored to avoid unnecessary merge conflicts.
