#1 Open commands should support goto line

Similarly how you can start up ait with ait file.txt +num, the open commands should also accept this format. The programs would just need to output file.txt +num to STDOUT.

Most grep-like commands only show positive line numbers so it didn't make sense to do it like how the command line interface works. Also, some files have spaces in the names so it's easier to parse if I use a colon. Look at scripts/gg (git grep) to see an example.