A new filter to programatically edit the tail end of the commit log
messages.
* cc/interpret-trailers:
Documentation: add documentation for 'git interpret-trailers'
trailer: add tests for commands in config file
trailer: execute command from 'trailer.<name>.command'
trailer: add tests for "git interpret-trailers"
trailer: add interpret-trailers command
trailer: put all the processing together and print
trailer: parse trailers from file or stdin
trailer: process command line trailer arguments
trailer: read and process config information
trailer: process trailers from input message and arguments
trailer: add data structures and basic functions