Make max temp table size settable

The fixed max temp table size would be not enough for complex queries. For example, a query with aggregate function and GROUP BY statement on 10 GB data on my two voltdb nodes. Making it settable should be better and flexible.

This is not what you really want. 

Be default, we use 100MB as the limit for temp table space if the user does not tell VoltDB server from deployment file. If you really want to run large aggregate queries and want to increase this limit, you should set it in your deployment file when starting VoltDB server.

Examples like:
    <systemsettings>
        <temptables maxsize="500"/>
    </systemsettings>

Docs link:
http://voltdb.com/docs/UsingVoltDB/ConfigStructure.php