Flipping the display

[HoseanRC]

I added a simple code to rotate every digit in a display and flip their position to rotate the whole display

this works by swapping bits 0, 1 and 2 of the digit with bits 3, 4 and 5
this works like so:

 --0--           --3--
|     |         |     |
5     1         2     4
|     |         |     |
 --6--           --6--
|     |         |     |
4     2         1     5
|     |         |     |
 --3--  .7       --0--  .7

[HoseanRC]

this have been tested with tm1650

[maxint-rd]

Excellent, thank you for your contribution!
When I have time I will review your PR and merge it.