Add command (show-local?) to show information about a locally installed package

[jmckisson]

Currently 'mpkg show' only works if a package is listed in the repository. It may be useful for mpkg to list the description and other information about a package that is installed locally that is not in the repository.

[vadi2]

It would be good of if we had one command to handle all the cases, this would make it easier for the player to use.

Adding separate commands would offload the choice of picking the right command for the right scenario onto the player and that's not ideal

[ZookaOnGit]

How about mpkg show shows

• the installed version, if installed
• the repo version, if not installed
• the installed version, and if there is a repo version of a higher version, an echoLink to view it (after displaying the installed version)
  ?

[vadi2]

I think that would be great

[ZookaOnGit]

fixed in #151