unrecord: show list of changes if none were given as arguments

How many changes are shown is controlled by the –show-changes command line option and the unrecord_changes global option (the former takes precedence). As part of this change, the make_changelist and parse_changelist functions are moved from pushpull.rs to commands/mod.rs so that unrecord can use them.

Created by  loewenheim  on December 16, 2020
SLJ3OHD4F6GJGZ3SV2D7DMR3PXYHPSI64X77KZ3RJ24EGEX6ZNQAC
Change contents