parse-dynparts: list free space on super

parse-dynparts: list free space on super

Added --free-space flag which allows to list free space on
super partition. Can be combined with --list-tables to print
table as multiple lines. Refactored parse-dynparts a bit so
it doesn't matter in which order --list-tables and --free-space
are given. Filename of super still has to be given as a first
argument to maintain compatibility with existing scripts.

Tests of parse-dynparts were refactored in order to be easier
to maintain. Test data is now created using functions from
liblp instead of external tools and hard to understand
operations on raw structures.

Change-Id: If6446618dae03ff31dc7972c94cc84781dc1b9bb