Add methods to the class table of Lua bindings.

[Possseidon]

For a functional style of programming it is very useful to have access to all the methods directly.

For example, given a table values of vec3, if one would want to sort them by length, then this:

table.sort(values, by(vec3.getLength))

is a lot nicer (and more performant) than this:

table.sort(values, by(function(vector) return vector:getLength() end))
-- or
table.sort(values, by(vec3().getLength))

(Where by returns a comparator based on the given projection function)