Version 0.15 released

This version of the SmallSQL Database include the follow changes:
- The HAVING clause has not work.
- A bug with date time functions in GROUP BY clause was fixed.
- Wrong ResultSetMetaData with GROUP BY was fixed.
- The follow SQL functions was added:
* CHAR
* DIFFERENCE
* INSERT
* LCASE
* LEFT
* LTRIM
* REPEAT
* REPLACE
* RTRIM
* SOUNDEX
* SPACE
* UCASE
- The number of JUnit tests was increased greatly.
There is now a block code coverage of 80% with the EMMA tool.