Investigate adding an is_a() function

[bit-hack]

Since we are a dynamically typed language, its natural that we will want to know what type something is. We can add a function to do this easily, but the problem is we need a specific type for types! Yet more keywords would be required for the following:

int
float
string
array
function

and one or more of the following functions:

is_a()
type_of()