Wrong type of currency created for MySQL

[php-coder]

For some strange reason type CURRENCY from Liquibase was translated into decimal(10,0) in MySQL. This leads to the bug when you're inserting 2.8 but it's rounded and inserted as 3.

Related to #198

CC @cssru: JFYI

[php-coder]

This is a possible fix:

mysql> ALTER TABLE series_sales MODIFY `first_price` decimal(10,2);
mysql> ALTER TABLE series_sales MODIFY `second_price` decimal(10,2);

[php-coder]

I decided to use DECIMAL(19,2) type to make it consistence with other currency fields.