Dirty macro warning + auto arity support

[bartkrak]

solves: membraneframework/membrane_core#757

[mat-hek]

@bartkrak could we also support passing a function without arity, that would match any arity? For example dirty :cpu, [:my_function, :another_function]

[bartkrak]

@mat-hek It's done. Now you can use macro in two ways:
dirty :cpu, [:something, :another_one] - without supplying arity, it will automatically determine correct one (assuming there is no way to define a multi-arity function in unifex, we talked about this)
dirty :cpu, something: 0, another_one: 1 - the old way for backwards compatibility.
In both cases if you misspell name of the function or provide incorrect arity you will get a nice warning.

[mat-hek]

instead of map and reject, use flat_map

[mat-hek]

Suggested change

	{dirty_name, dirty_arity} =
	cond do
	is_tuple(dirty_func) ->
	dirty_func
	is_atom(dirty_func) ->
	{dirty_func, nil}
	end
	{matched_name, matched_arity} = List.keyfind(functions_arity, dirty_name, 0, {nil, nil})
	if matched_name == dirty_name and (matched_arity == dirty_arity or dirty_arity == nil) do
	dirty_name =
	case dirty_func do
	{name, _arity} -> name
	name -> name
	end
	{matched_name, matched_args} = List.keyfind(functions_args, dirty_name, 0, {nil, nil})
	if dirty_func in [matched_name, {matched_name, length(matched_args)}] do

slightly more idiomatic, and you don't need functions_arity

[FelonEkonom]

Suggested change

	{functions_args, functions_arity} = Enum.unzip(functions_args_arity)
	functions_arity = Enum.map(functions_args, fn {name, args} -> {name, Enum.count(args)} end)

You don't have to create functions_args_arity variable, you can just create function_args the way it has been done before your changes and create functions_arity with a simple Enum.map, without second call of Enum.unzip, IMO it will simplify your code

[bartkrak]

after changes suggested by @mat-hek this is no longer necessary

[bartkrak]

@mat-hek I needed to add these nil checks to your suggestion, otherwise if List.keyfind() doesn't match length(matched_args) results in a crash