Allows alias for target in configuration file

[mlincett]

It could be nice if targets defined in the configuration file could be recalled through a user-defined alias, so that eget eget could be made to resolve to eget zyedidia/eget.

Most of the time it's easy to remember a software's name, much less its creator.

I am not sure whether this would be straightforward to implement or it would against the current configuration parsing mechanics, though.