Swap version and spec flags, switch split functions, Bug fixes
This is a minor tweak to 0.2.0 that swaps the --version <X>
flag to the more GNU-esque behavior of printing the software version when the --version
flag is passed (NB: no argument). The GFA output version can be controlled using the --spec <X>
flag.
This also swaps the gfakluge::split function for the pliib::split function, which should make swapping out to the zero-copy version easier.
A bug which caused a segfault when sorting GFA2 and outputting GFA1 was fixed.