v0.3.1

Not too much changed between v0.3.0 and v0.3.1, except for the addition of three new options in the command line.

• First, a memory limit option, so as to avoid bef killing your computer when it needs a lot of memory, instead just crashing.
• Second, a 'upgrade' option, that attempts to upgrade the size of the set of interleaved blocks into being approximately equal to the size given, or to the size of the input file if 0 is given. Useful when used in conjunction with minimize on small files, or with the seek option below on extremely large files.
• Third, a seek option, that is pretty much a hack in all honesty, that maps files to memory using mmap instead of using intermediate buffers. This is almost always slower than the default read/write dance, but is useful when you use some extremely large parameters that can't fit inside memory. It does have the catch of using an indeterminate amount of memory according to the kernel page cache (outside of my control) and having confounded performance characteristics, performing differently when under memory pressure, HDD vs SSD, etc. In some cases, when combined with the upgrade option, it can provide superior security than par2cmdline-turbo on extremely large files with better performance, but that is highly dependent on the environment and in most cases it performs worse.