Update main.java

removed player array & username persistence in config.yml, implemented file checking for player.dat to check for new players. Added fetching from config for welcome message.
Update config.yml

Added keys/values to be fetched for the Welcome message.
Update README.md

Updated descriptions and information pertaining to the last update in the code/config.
updated plugin version to 1.1

updated to reflect version changes of a minor update
Merge pull request #1 from savedbygrace979/master

Minor functionality update with added features