Kiwi1969 blanker 1 (#136)

* Updated to work on V4SA

Now clears the window, activates window, and hides mouse pointer whilst blanking.
Existing code to use blitter copy/rectfill was commented, as glitter code was not working right. (Prior commented code for CPU alternative was restored)

* Update Blanker.c for version 1.00 and improvements

* Fix copyright symbol in Blanker.c

* Add initial WaitTOF call in Blanker.c

* Revert to prev commit

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Co-authored-by: Willem Drijver <60568860+WDrijver@users.noreply.github.com>

Author: kiwi1969