Support for different actions

[skuntz]

Define a set of actions and their commands to be used with the watchpoints.

• Interactive console - interactive
• Print trace buffer to console - printTrace
• Print trace buffer to output / file - dumpTrace? printTraceFile
• Trigger checkpoint at next sync? - checkpoint
• Print status (debug info defined in component)?
• Others like interacting with trace buffers, adding/deleting/modifying watchpoints

[skuntz]

sstsimulator#1452