Write-thru mode testing animation

[hornc]

The Title stays on screen using display storage
the 2 frame "rotating" lines | - are drawn using Write-thru mode ... they look like + presumably at 30 fps. Need to investigate how to control the frame rate. ct.py's --hold arg only affects CLS

Exploring alternatives relating to #33

[hornc]

Adding ZFILL 80000 (to title and the dummy fill parts) and CLEAR 80000 adds and removes 80K zeros to the datastring to introduce a delay between frames which confirms that the write-thru animation is working as expected... there has to be a better way to control the timing though.