Add icons and update

[KINGSABRI]

Hello!
Thanks for making this gem available.
There are couple of ideas here that I think will be good to have

1. Add icons and returns it encoded with base64 or returns the icon absolute path or find a better solution for that.
2. Add a way to update apps.json file from the official main stream repository.

Something like:

Wappalyzer::Update.check   # @return Boolean  
Wappalyzer::Update.apps_json   # @return Boolean
Wappalyzer::Update.icons   # @return Boolean
Wappalyzer::Update.all   # @return Boolean

This will decrease the possibility of forcing ppl to upgrade the gem when no Ruby code has been added and make sure they're updated with latest official udates

[rbucks]

Is anyone working on this?