Replaced substring function with the library function table.concat
Introducing the ability to block users from downloading from moderators and above.
Fixed bug ( earlier, the second branch of if was never visited since table.concat returns empty string instead of nil)
Changes to the permission checking function.

Now , mute,unmute etc dont require the user to be online
Replaced string.find with string.match
Fix spelling mistake
Merge pull request #2 from siddhu323/Block

Block