Revert the vim_mode setting for now, needs a rethink

There have been too many bugs reported in vim_mode, and
the proposed fixes are increasingly fragile - hence we
have decided to back it out for now.  For reference:

   https://github.com/htop-dev/htop/issues/69
   https://github.com/htop-dev/htop/pull/37
   https://github.com/htop-dev/htop/pull/106

The whitespace changes also arrived in commit 12805f61d
not sure what that was about, but backed out as well.

Settings.h

@@ -20,7 +20,6 @@ typedef struct {
 
 typedef struct Settings_ {
    char* filename;
-
    MeterColumnSettings columns[2];
 
    ProcessField* fields;
@@ -50,7 +49,6 @@ typedef struct Settings_ {
    bool accountGuestInCPUMeter;
    bool headerMargin;
    bool enableMouse;
-   bool vimMode;
    #ifdef HAVE_LIBHWLOC
    bool topologyAffinity;
    #endif