#101 Add REGEXP regular expression comparison

[Simon Chenery]

Add REGEXP comparison, similar to a SQL LIKE expression, but matching a string against a regular expression (in java.util.regex.Pattern format) instead.

For example,

SELECT * FROM t1 WHERE RefId REGEXP '^[0-9]{6}$'

SELECT * FROM t2 WHERE Partnum NOT REGEXP 'XXX-(11|22|50|99|100)'

Other databases such as sqlite and MySQL have REGEXP. PostgreSQL has ~ to perform a regular expression matching.