sys/xvimage/xvimagesink.*: Add a "draw-border" property that can be set to false to disable drawing borders.

Original commit message from CVS:
* sys/xvimage/xvimagesink.c:
* sys/xvimage/xvimagesink.h:
Add a "draw-border" property that can be set to false to disable
drawing borders.
* tests/icles/test-colorkey.c:
* tests/icles/Makefile.am:
Add new test application for the colorkey handling.