+ improved checking if the SHELL environment variable holds a valid shell:
+ introduced TTerminal.Update
* the creation of the terminal input output connection and the spawning of the
* check if Assigned(FInputOutputConnection) inside TTerminal.HandleInputOutput
+ expose terminal's input output connection as a property
+ enabled -gh option for mem leak detection when building with the lazarus project file
* fix memory leaks after ptckvm finalization
* TTerminalInputOutputConnection converted to an interface: ITerminalInputOutputConnection