Disabling old split view, adding default shortcuts...

so, code quality is NOT really good... I just hack this together to make it work more like I wanted it to behave.

- old split options are not readilly available, but there sure remain codes to delete.
- options in the menu no longer appears and I did not care too much
- I use keyboard shortcuts, I used something similar to what iTerm2 on OSX has a default
Meta-d to split horizontally and Meta-Ctrl-d to split vertically
- Meta-w close that has focused.
- we still have that bug where the window remains open with no more terminal after closing the last one
- simplify code where I could, reusing existing signals instead of creating new ones...