add sample for 'fillscreen' block
update everything.ta to include 'fillscreen' block
add sample for the 'set color' block
add sample for the 'set shade' and 'set gray' blocks
add sample for the 'color', 'shade', and 'gray' value blocks
add 'heading' value block to set-heading.ta (from mz-samples)
sample for the 'pen up' and 'pen down' blocks
sample for the 'set pen size' block and the 'pen size' value block
add sample for the 'start fill' and 'end fill' blocks
update everythin.ta to include all exportable blocks