Add documentation of onSchemaCreateTableColumn, onSchemaDropTable and onSchemaAlterTable
Add documentation of onSchemaCreateTableColumn, onSchemaDropTable and onSchemaAlterTable

mikeSimonson/dbal,lcobucci/dbal,stof/dbal,BenMorel/dbal,lcobucci/dbal,Tobion/dbal,deeky666/dbal,drieschel/dbal,vortgo/dbal,mikeSimonson/dbal,gencer/dbal,doctrine/dbal,stof/dbal,stchr/dbal,drieschel/dbal,stchr/dbal,vutung2311/dbal,deeky666/dbal,doctrine/dbal,kimhemsoe/dbal,kimhemsoe/dbal,gencer/dbal,vortgo/dbal,BenMorel/dbal,Tobion/dbal,vutung2311/dbal