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 ScrollLt_width 14
#define ScrollLt_height 14
static unsigned char ScrollLt_bits[] = {
0x00, 0x00, 0x00, 0x03, 0x80, 0x03, 0xc0, 0x01, 0xe0, 0x00, 0x70, 0x00,
0x38, 0x00, 0x38, 0x00, 0x70, 0x00, 0xe0, 0x00, 0xc0, 0x01, 0x80, 0x03,
0x00, 0x03, 0x00, 0x00};