Issue #130: Fixed support for indenting by tab
Allow indent a block of code by selecting a range of lines
and pressing 'tab'. The behavior implemented is the same as
the one in Sublime Text editor since I found it intuitive enough.
#define ScrollLtMotif_width 12
#define ScrollLtMotif_height 11
static unsigned char ScrollLtMotif_bits[] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x01, 0xe0, 0x01, 0xf8, 0x01,
0xe0, 0x01, 0x80, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};