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 ComboDn_width 14
#define ComboDn_height 14
static unsigned char ComboDn_bits[] = {
0x00, 0x00, 0x00, 0x00, 0xe0, 0x01, 0xe0, 0x01, 0xe0, 0x01, 0xe0, 0x01,
0xf8, 0x07, 0xf0, 0x03, 0xe0, 0x01, 0xc0, 0x00, 0x00, 0x00, 0xf8, 0x07,
0x00, 0x00, 0x00, 0x00};