Use huge line buffer like a pro

Another proof that 640KB won't be enough for everybody.

dotfiles.config/Xlib/global.Xdefaults

 URxvt.scrollWithBuffer:     true
 URxvt.scrollTtyOutput:      false
 URxvt.scrollTtyKeypress:    true
-URxvt.saveLines:            32767
+URxvt.saveLines:            1048576
 
 !## cursor & pointer
 URxvt.cursorUnderline:      false