Change GLib size units policy
This commit changes GLib size units policy. We now prefer SI units and allow for use of proper IEC units where desired. g_format_size_for_display() which incorrectly mixed IEC units with SI suffixes is left unmodified, but has been deprecated. g_format_size() has been introduced which uses SI units and suffixes. g_format_size_full() has also been added which takes a flags argument to allow for use of IEC units (with correct suffixes). It also allows for a "long format" output which includes the total number of bytes. For example: "238.5 MB (238,472,938 bytes)".