Version 0.13 released

This version of the SmallSQL Database include the follow changes:
- The precision for varchar and varbinary was saved wrong with 38 before.
- Negativ numeric and decimal values was rounded wrong with the getInt() method.
- The prefix "file:" on the database name will be ignored now. This is valid
for the methods getConnection() and setCatalog() and for the SQL commands
CREATE DATABASE, DROP DATABASE and USE DATABASE.
- The URL property "dbpath" and "create" was added.