Display the available commands when no valid command type is recognised. Also when program first runs.

[newbishme]

When the user open the program, update status bar to list all the available commands.

When the user input unrecognised input, update status bar to Error + Valid commands < list all the available commands. >

Example: User input: "hello world" Status bar: "Error! Valid commands: add addt addd ... ... ..."

[pyonghe]

Issue resolve in 528d968