Implicit arguments for anonymous functions

[brollb]

Anonymous functions in NetsBlox/Snap! have implicit arguments when none are specified as shown below. The generated code should reflect these same rules.

When arguments are specified (even if unused), empty slots are evaluated to "0":

If no arguments are specified and it is called with a single value, all empty slots will be filled with the given value.

If the number of inputs passed matches the number of empty slots, then the inputs are passed to each empty slot.

[brollb]

This is higher priority since it is a common practice (especially with the map block)

[brollb]

However, I don't think the last case is very common so I am moving that to #105