add Zend\Db\Sql\Ddl\Column\BigInteger to allow BIGINT type
remove unused var and __construct that already defined in parent class
fix some typo docblock
PR #4500
Merge branch 'add/ddl.columnBigInt' of git://github.com/samsonasik/zf2 into samsonasik-add/ddl.columnBigInt
Merging PR #4500
Merge branch 'samsonasik-add/ddl.columnBigInt'