removed the loop check for duplicated vertices in the add operation of Graph
removed the loop check for duplicated vertices in the add operation of Graph

orientechnologies/orientdb-php-odm,orientechnologies/orientdb-php-odm,doctrine/orientdb-odm,Krienas/orientdb-php-odm,doctrine/orientdb-odm,Krienas/orientdb-php-odm,ruleant/orientdb-odm,ruleant/orientdb-odm