Option to clean up memory periodically/manually

See the screenshot - we'll add option to configure periodic calls to Java GC + option to call it manually using link below the log window.
Clicking on link will call System.gc() on the backend.


If set to periodically, it will use a timer and call System.gc() in predefined time intervals.


Time intervals in combo box:
Never
10 seconds
20 seconds
30 seconds
45 seconds
1 minute
2 minutes
5 minutes
10 minutes
15 minutes
30 minutes
1 hour


Description text:
Clean memory periodically by explicitly calling Java Garbage Collector.  
Use it if you experience problems with memory, otherwise keep it turned off.
Java does this autoatically and it usually does a very good job. 
Turning it on without reason might slow down the application.