Fixed errors with DB regarding backticks, group field names and primary keys

After trying to install the plugin, i received a lot of errors in the WP Admin regarding MYSQL syntax errors.

1) Removed backticks --> 
http://codex.wordpress.org/Creating_Tables_with_Plugins
You must not use any apostrophes or backticks around field names.

2) Renamed the column 'Group' -->
http://dev.mysql.com/doc/refman/5.0/en/reserved-words.html
Group is a reserved word

3) Changed Primary Key to Unique Key -->
Similar in function but allows dbDelta to work properly
http://onetarek.com/wordpress/wordpress-dbdelta-database-error-multiple-primary-key-defined/
http://stackoverflow.com/questions/3844899/difference-between-key-primary-key-unique-key-and-index-in-mysql