increment required go version
update readme

I've added an explanation of the options in the readme.
add popularity sorting
improve usage in readme
update xdg dependency
switch xdg dependencies

Just migrating them off of my fork. Go's package system is much more
effective and useful than when I originally wrote this so there's no
real need to maintain a fork.
create test for checkName
clean up main function

Gave the code block a little breathing room, removed the date + prefix
from the logger, and made the "couldn't find any entries" actually
return an error code.
improve comments
simplify checkName function
move main to top of file
simplify boolean
add more spacing in manpage
cleanup README usage
upgrade license to GPL3
simplify directory walking
update readme resources
remove old todo file and add issue tracker to readme