Merge branch 'cc/git-packet-pm'

Parts of a test to drive the long-running content filter interface has been split into its own module, hopefully to eventually become reusable. * cc/git-packet-pm: Git/Packet.pm: extract parts of t0021/rot13-filter.pl for reuse t0021/rot13-filter: add capability functions t0021/rot13-filter: refactor checking final lf t0021/rot13-filter: add packet_initialize() t0021/rot13-filter: improve error message t0021/rot13-filter: improve 'if .. elsif .. else' style t0021/rot13-filter: refactor packet reading functions t0021/rot13-filter: fix list comparison