Add an 'info' command

[0xdevalias]

Not sure if it's possible, but it would be awesome to have a mas info type command to get more details about the package/id. (similar to homebrew)

⇒  brew info mas
mas: stable 1.2.0 (bottled)
Mac App Store command-line interface
https://github.com/argon/mas
/usr/local/Cellar/mas/1.2.0 (4 files, 6.1M) *
  Poured from bottle
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/mas.rb

mas info 123456
mas info Some App Name Here

If possible, maybe the app name, short description, link to the full appstore page, and whether it's installed or not?

Edit: Looks like the itunes lookup api would provide the required bits of info for this:

Eg. https://itunes.apple.com/lookup?id=886106985

Useful Sounding Keys: kind, features, supportedDevices (filter for OSX), advisories (maybe), fileSizeBytes, averageUserRatingForCurrentVersion, userRatingCountForCurrentVersion, trackContentRating, trackCensoredName, trackViewUrl, contentAdvisoryRating, minimumOsVersion, formattedPrice, wrapperType, version, currency, artistId, artistName, genres, price, description, trackName, trackId, bundleId, releaseDate, primaryGenreName, currentVersionReleaseDate, releaseNotes, sellerName, averageUserRating, userRatingCount

Other Keys: screenshotUrls, ipadScreenshotUrls, appletvScreenshotUrls, artworkUrl512, artistViewUrl, artworkUrl60, artworkUrl100, isGameCenterEnabled, languageCodesISO2A, isVppDeviceBasedLicensingEnabled, primaryGenreId, genreIds

As one possible example:

trackCensoredName: version [currency price or formattedPrice] (genres)
By artistName(or sellerName)
description(limit length to something reasonable)...
Current Rating: averageUserRatingForCurrentVersion, Overall Rating: averageUserRating
sellerUrl
Released: currentVersionReleaseDate
Min OS: minimumOsVersion(could check this against system)
Size: fileSizeBytes(calculated to a pretty value)
From: trackViewUrl

[phatblat]

This has been added in #55