add support for LIMIT with only one row count JDBC parameter

[jujusharp]

This is a enhancement for LIMIT with ONLY ROW COUNT JDBC parameters.
e.g.

SELECT * FROM mytable WHERE mytable.col = 9 LIMIT ?1

OR

SELECT * FROM mytable WHERE mytable.col = 9 LIMIT :param_name

[coveralls]

Coverage remained the same at 84.715% when pulling 9ffc2df on ibeam-cn:master into 1315d03 on JSQLParser:master.