@update
<> move the drivers' context into the trace session
<> add "special" constructor for a "pre-initialisation", usefull to move the
callgraph generation into its specific menu part.
@fix
<> when the TRACER_CALLGRAPH is not set, the callgraph was always generated. (fixed)
@update
* callgraph: add "export <filename>", to export callgraph information to the SMEM.
* input: input_display(): add meta information (cursor mode)
* input: input_read(): allow user to add prefix text.
* input: add input_write_noint(): display and doesn't wait user interaction.
@add
* callgraph: add menu
* callgraph: Generate the callgraph even if a breakpoint has been placed after a subroutine.
@fix
* disable the UBC when we are in the "user" handler (more stability)
* the key [EXE] has been mapped by the GUI and exit the handler when pressed.