Clear listing button

This will wipe out the time lord sequences for a fresh calculation.  This button isn't really necessary because selecting a new time lord procedure will clear the required lists out.

• Time Lord Graph
• Chart Selection drop down list
• Starting Date field
• Time spanspin  edit
• Draw button
• Clear button
• Time lord options button

• Time Lord List
• Chart Selection drop down list
• Time lord method drop down list
• Optional starting point selection drop down list
• Period length spin edit field
• Viewing general and sub periods
• Exporting general and sub period lists
• Printing general and sub period lists
• Clear listing button
• Font button
• Calendar button