Error / Warning report formatting of `lint` command

[mrylmz]

The current reports of lint errors and warnings contain too much informations.

It would be a great advancement of the tool to reduce the informations reported to a more user-friendly representation.

Improvement suggestions:

• Categorizing Reports by Type
• Highlighting the issue sources with colors
• Better indentation and formatting for readability
• Removing informations about the executed commands like diff ...